1.1.

University of Rochester Integrated Nanosystems Center

The URnano was created in 2011 through funding from various U.S. government agencies with grants totaling four million dollars. NY Congresswoman L. Slaughter aided in obtaining these grants. This center is truly interdisciplinary, involving faculty and students from the departments of optics, chemistry, physics, biomedical, chemical, mechanical, and electrical engineering and the UR Medical Center.

Currently, UR has a centralized 2000-square-foot, class-1000, clean-room nanofabrication facility linked with nanometrology instruments. URnano houses scanning electron (with a focused ion beam), transmission electron, atomic force, and optical microscopes; deposition and etching equipment; and devices capable of lithography at nanoscales. The real-world applications pursued at URnano include new fuel cells, new dialysis techniques, and new devices for detecting ultra-small quantities of biological materials. The URnano website is provided.³⁰ URnano also offers training to faculty, students, and outside researchers to become certified in the use of these tools.

1.2.

Monroe Community College (Rochester, New York)

MCC’s Engineering Science/Physics program is a rigorous academic curriculum designed to facilitate transfer into B.S. Engineering/Physics programs.³¹ To date, the graduates of this program have transferred to over 30 four-year institutions in NY State and nationally, and the MCC has $2+2$ dual admission agreements with UR biomedical, chemical, electrical, and mechanical engineering, and optics. In addition to STEM majors, non-STEM liberal arts majors benefited from collaboration with UR. About $\sim 44\%$ of MCC students are minorities, and 58.7% are women (data of fall 2020).

2.1.

Required Nanometrology Laboratory Class (OPT 254/PHY 371)

The prerequisite class for the Certificate, Nanometrology Laboratory OPT 254/PHY 371, quickly became popular: the clean-room limited the maximum number of students from six to eight students. The instruction proceeds entirely through direct student-professor contact at all times. Three-course modules were taught by three instructors: (1) electron microscopy [scanning electron microscopy (SEM) and transmission electron microscopy (TEM)], McIntyre and Lukishova; (2) optical microscopy (wide-field and confocal fluorescence microscopy of single nanoemitters), nanoobjects/nanoengineering/quantum nanophotonics, Lukishova; and (3) atomic force microscopy (AFM) (started by Papernov and continued by Lukishova). The electron microscopy module consists of (1) six 1.5-h lectures and two 2 to 3-h labs (SEM and TEM), (2) the optical microscopy module includes five 1.5-h lectures and four 1.5-h labs, and (3) the AFM module contains two 1.5-h lectures and three 1.5-h labs.

Throughout the semester, students face three exams (in each module separately) and are required to submit individual lab reports for each module (during the pandemic years, students submitted an essay on electron microscopy instead of a lab report).

2.2.

Undergraduate Research and Design Projects

The scientific direction of research topics for CNSNE depends on a specific department. UR is a top research university with professors leading cutting-edge projects; therefore, all students working toward their certificates are members of strong scientific groups. Design projects are created based on industry demands to solve technological problems of companies. For design projects, students working in groups of three to four have two advisors: a company representative (primary customer) and a UR faculty member. During the two-semester-project, students regularly communicate with primary customers, although the design projects are conducted at the UR. In addition, all design and senior thesis projects are discussed and graded in a separate class, OPT 320/321 Senior Design and Senior Thesis (Professor Knox), which includes more than CNSNE projects. After this class, students submit reports, deliver talks, and present posters on UR Senior Design Day. Table 1 gives the statistics of various stakeholders on the accomplished students’ projects: 45 students (by May 2022); eight of them involved in the design, 37 in research projects, four companies, and 44 professors participated in advising students.

Table 1

Stakeholders’ statistics of completed research and design projects toward the CNSNE.

Some research projects advised by the UR professors are listed below:

The stakeholders’ companies in the students’ design projects in CNSNE during these years were ASML [nanostructure antireflection coating (primary customer Dr. Kelkar, UR faculty advisor Professor Kruschwitz)], Harris Corp. [quantum key distribution (QKD) system design (primary customer Dr. Bucklew, UR faculty advisor Professor Lukishova)], Sydor Optics [nano-roughness scatterometer (primary customer Dr. Hobbs, faculty advisor Professor Knox)], Materion [design, fabrication, and testing of new types of mid-infrared wavelength optical filters using nanofabrication technology (primary customer Dr. Tatarek, faculty advisor Professor Vamivakas)].

2.3.

Elective Classes for the Certificate

Among the elective classes for CNSNE, the most popular class is OPT 253 Quantum and Nano-Optics Laboratory.^25–28 This four-credit-hour class consists of four, 6- to 15-h laboratory experiments in quantum and nano-optics accompanied by lectures (see Ref. 28 of this issue in which this class is described in detail).

Because of the lack of space in the UR Curriculum for new classes, we modified a required class for optics and optical engineering majors, OPT 204 Sources and Detector Labs and Lab Lectures (Lukishova) by adding content on nanoscience, nanotechnology, and quantum nanophotonics. To satisfy Certificate program requirements, we included several new lab experiments: (1) with CdSe nanocrystal quantum dot (NQD) solutions as bright fluorescence sources and the calculation of their sizes from spectral measurements; (2) on measurements in a spectrophotometer, a reflectivity of liquid crystal photonic bandgap material showing photonic stop band; and (3) comparison of photon statistics from laser- and pseudothermal-light sources with a single-photon counting detector, which is widely used in nanoscience. In addition, in the two lecture workshops on lasers and nonclassical light sources, nanolasers and nanophotonic advances for antibunched photon sources and entangled and squeezed-photon sources are discussed. In Sec. 4, more details are described on the introduced mini-labs in nanophotonics (see also Ref. 28 of this issue for quantum optics experiments of this class).

2.4.

Undergraduate Students’ Training Abroad During the Summer of 2016

In the summer of 2016, nine UR optics undergraduate students took part in educational events in Moscow and St. Petersburg as part of the U.S.–Russian collaboration.^32–34 In Moscow, UR students were immersed for five days in cutting-edge research, technologies, and ideas on offers by Russian, European, and U.S. scientists at the National Research Nuclear University MEPhI, International School on Optics and Laser Physics.^32,34 This experience also included tours of the MEPhI’s Center on Nanotechnology with its clean-room facility for electronic components and nano-bioengineering laboratory. UR students also visited laboratories at the Lebedev Physical and General Physics Institutes of the Russian Academy of Sciences. These include facilities for the growth of diamond thin films and nanocrystals with single defect centers. The students also learned about cutting-edge research on NQDs. After one week in Moscow, students moved to St. Petersburg to participate in research projects on photonics, nanophotonics, and quantum information in the scientific laboratories of the International Institute of Photonics and Optical Information Technologies of ITMO University.^33,34 Two UR students had the opportunity to work directly with ITMO researchers on a QKD system. Before becoming quantum network operators, they learned about QKD through lectures and seminars. They performed a secure transfer of encrypted messages that contained the logos of both UR and ITMO between two ITMO buildings. After returning to Rochester, one of the students used the skills acquired in ITMO to set up an in-air orbital-angular-momentum QKD system between two UR buildings.³⁴ After the ITMO researches, each UR student delivered 15-min talks about their results and obtained the Certificates of this School on Photonics. These collaborations with Russian institutions were outlined in the magazine of the Optical Society OSA (Optica) Optics & Photonics News.³⁴ Some students’ comments in their written interviews after their MEPhI visit were as follows:

Several students on this trip have already been awarded the UR CNSNE.

4.1.

Using Schrödinger Equation for Calculation of Sizes of Quantum Dots from Spectral Measurements

We adopted the idea of this mini-lab from the NanoSys Company, which offered some teaching materials for sale. The UR used NQDs with different fluorescence wavelengths from the UR Chemistry Department (Krauss).

The electronic and optical characteristics of NQDs are driven by their size and shape. For example, the bandgap of a semiconducting NQD is inversely proportional to its size. In fluorescence applications, the frequency of the emitted light shifts as the size of the quantum dot decreases.

For a semiconducting NQD to produce photoluminescence, an exciton (electron–hole pair) must be created. Photoluminescence results from the recombination of each pair. In this laboratory, excitons are created by the absorption of UV or blue light.

Solutions of colloidal NQDs in vials were excited by either the blue light of a laser pointer or a special UV source, as shown in Fig. 3(a). Students wore UV-protective goggles during the experiment. NQD fluorescence spectra were recorded using an Ocean Optics spectrometer [Fig. 3(b)].

Fig. 3

Nano-mini-lab #1 of the OPT 204 class sources and detectors. (a) Three solutions of NQDs and the UV source for excitation of NQD fluorescence. (b) A typical fluorescence spectrum of NQDs.

To calculate the size of the NQDs from their fluorescence wavelength maximum, the NQDs were modeled as quantum particles in a box with discrete energy levels. From the solution of the time-independent Schrödinger equation for a particle in a box (infinite potential well) in a three-dimensional case, the dependence of energy $E$ on the radius $R$ is derived in the form

4.2.

Cholesteric Liquid Crystal Photonic Bandgap Structures and Their Application in Quantum Optics

Planar-aligned cholesteric-liquid-crystal (CLC) structures exhibit one-dimensional (1D) photonic bandgaps (light at a certain frequency band is reflected) for the handedness of circularly polarized light, the electric field vector of which follows the rotation of the CLC molecular director. The stopband is centered at wavelength ${\lambda }_{\mathrm{o}}=p(n_{\mathrm{e}}+n_{\mathrm{o}})/2$, where $p$ is the pitch of the CLC spiral structure and $n_{\mathrm{e}}$ and $n_{\mathrm{o}}$ are the extraordinary and ordinary refractive indices of the molecules, respectively. The bandwidth of the transmission stopband is given by $\mathrm{\Delta }\lambda =p(n_{\mathrm{e}}-n_{\mathrm{o}})$.

Planar alignment of CLC materials is among the simplest methods for the preparation of photonic bandgap structures. They can be prepared from a cholesteric oligomeric powder by heating the powder between two cover-glass slips on a hotplate ($\sim 70°\mathrm{C}$ to 100°C) to the liquid state. In the liquid state, the cholesteric material is sheared between substrates for planar alignment. Once cooled to a glassy (solid) state, the liquid crystal alignment remains preserved. Attractive colors appear from the initially uncolored powder oligomers, indicating photonic bandgap (selective reflection) structures. Using a monomeric (liquid form at room temperature) CLC, the preparation of a photonic bandgap requires only 1 min. A drop of a monomeric, cholesteric liquid crystal should be placed between two glass slips; after shearing, a uniform color from an initial milky liquid crystal appears.

This lab was very popular among middle and high school students and their parents during the Institute of Optics Family Day. OPT 204 students measured the reflectivity of the prepared CLC photonic bandgap structures during their lab on spectroscopy of different light sources and radiometry using a Konica Minolta CM-3700 A spectrophotometer with an integrating sphere [Fig. 4(a)]. The inset (left) shows samples of the photonic bandgap CLC structures. The spectral dependence of the reflectivity of a sample is shown in Fig. 4(b) (spectrophotometer user interface).

Fig. 4

Nano-mini-lab #2 of the OPT 204 class Sources and Detectors. (a) Input port of an integrating sphere inside a spectrophotometer. CLC samples between two glass substrates are shown in the insert. (b) A selective reflection curve (spectral dependence of reflectivity) of the photonic bandgap CLC structure was obtained on this spectrophotometer.

Liquid crystal examples were used in an OPT 204 lecture workshop on nonclassical light sources.^35,36 Entangled sources, indistinguishable photons, and a Hong-Ou-Mandel interferometer³⁷ were described, and examples of experiments with 1D photonic bandgap CLC structures in a Hong-Ou-Mandel interferometer at the Institute of Optics were discussed.^38–41 In addition, students learned about single-photon sources based on single-emitter fluorescence in planar-aligned liquid crystal hosts and other micro- and nanostructures for tailoring the properties of the emitted single photons.^35,36

5.1.

Students of Monroe Community College

The following is one example from the spring of 2015 involving MCC students. They completed both pre- and post-experience Cleanroom Access quizes. The pre-assessment was delivered prior to formal instruction and lab experience at the UR, although during lectures at MCC, all questions were discussed; post-assessment measures were administered following the labs. The questions of this quiz are shown in Fig. 5, which also includes the pre- and post-test item scores, pre-test/post-test changes, and normalized gain scores. Gain scores were calculated as follows:

Fig. 5

Evaluation of knowledge of MCC students (provided by Professor Zawicki): A Cleanroom Access quiz (maximum pre-test and post-test value equal to 1 corresponds to 100% of students correctly answering this particular question).

Students were generally able to answer the five questions, addressing general working procedures, at the mastery level ($>83\%$) even on the pre-test. Students were able to respond to the need for gloves and glasses, as well as for a buddy. The two questions addressing the use of calcium gluconate and the proper response to skin contact with hydrofluoric acid were the most difficult for students. Only 58% of students correctly answered questions about calcium gluconate in a pre-test and post-test quiz. Selecting three correct options of what to do in a case of skin contact with hydrofluoric acid from six options, most students answered unsatisfactorily, even with negative gain scores. The instructors should find better ways to explain to students these important safety issues in a photolithography laboratory. However, most of the data provided evidence that MCC students were benefiting from the laboratory experiences at the UR.

5.2.

Technical Elective OPT 253 Class Quantum and Nano-Optics Laboratory (Sophomores-Seniors)

UR students of this advanced lab class (Sec. 2.3) were also evaluated with the help of Professor Zawicki. OPT 253 was taught as a technical elective class with a maximum of twenty students in the class. In fall 2015, eleven students completed both pre- and post-assessments on an AFM quiz. The questions and the assessment data (item difficulties both pre- and post-experience, the change in item difficulties, and the normalized item gain scores) are shown in Fig. 6.

Fig. 6

Evaluation of knowledge of OPT 253 students (provided by Professor Zawicki): An AFM quiz (maximum pre-test and post-test value equal to 1 corresponds to 100% of students correctly answering this particular question). Later an AFM lab was transferred to the OPT 254 class.

All five questions, which addressed the operation and significance of AFM, were initially tested and ranged from 0.55 to 0.82 difficulty level. The post-test scores for these items ranged from 0.91 to 1. Gain scores ranged from 0.5 (what is the difference between a profilometer and an AFM?) to 1 (all other questions). The data provides substantial evidence of student learning.

Success in bringing advanced quantum photonics and nano-photonics concepts to undergraduate students was evaluated by a written survey of these eleven undergraduate students with the following questions:

All students answered “yes” to these questions. One typical example of students’ answers follows:

5.3.

OPT 254/PHY 371 Nanometrology Laboratory Class, Required for CNSNE (Sophomores-Seniors)

The survey was conducted in the spring of 2022 with five highly motivated students after finishing this advanced Nanometrology Laboratory class (see Sec. 2.1). Practically all students taking this class are working toward the CNSNE, and their grades, both for lab reports and quizzes, sometimes exceed the maximum 100 points for each assignment. We conducted a study on the self-efficacy of these students. According to Refs. 42 and 43 and a definition of Ref. 44, self-efficacy is a set of beliefs about an individual’s own capacity that impacts an individual’s choices and the effort that they put forth to complete a task and accomplish goals. For this study, two questions were included in the survey:

All of the students answered yes to both questions. For instance, one student answered that she is more confident now after taking this class.

Another survey asked about the work environment in nanotechnology and what they would do on a daily basis if they chose this career path. All students preferred a lab environment over modeling, for instance “making samples, preparing experiments, testing new methods.” Answering a multiple-choice questionnaire about future careers after college, all students selected “science/engineering/medicine.” One student also added education/teaching, one added patent law, but nobody selected business.

5.4.

OPT 204 Sources and Detectors Labs and Lecture Class (Juniors-Seniors) with Nano-mini-labs

The 15-mins “nano-mini-labs” introduced to OPT 204 are described in Sec. 4. In spring 2022, we conducted two pedagogical research surveys in this class: (1) on students’ understanding of nanoobjects and nanostructures and (2) on students’ attitudes toward working in nanotechnology, including their self-efficacy. Figure 7 shows two questions and a histogram from a final “Big” quiz of the percent of 42 students answering correctly these questions on nanoobjects and nanostructures that they investigated in their lab on spectroscopy of different light sources and materials. Almost all students answered either correctly (76.2/66.67%) or partially (23.8/28.57%) to these questions. Partially means that these students did not describe experiments with nanoobjects/nanostructures although they identified both NQDs and CLCs photonic bandgap structures. Only two students (4.76%) were unable to identify cholesteric liquid crystal photonic bandgap nano/microstructures characterized in a spectrophotometer.

Fig. 7

Evaluation of knowledge of OPT 204 students from the final “Big” quiz. TOP: two questions on nanotechnology; BOTTOM: a histogram of the percent of students answering correctly, partially, and incorrectly these two questions.

Two surveys were conducted at the end of the semester on students’ attitudes toward nanoscience and nanotechnology. The questions of the first survey are listed in Fig. 8. Figure 9 shows four histograms of a percent from 34 students answering these questions. Although 87.9% of students are interested in nanotechnology, only 33% of them are thinking about a career in this field. Question #3 in Figs. 8 and 9 was practically the same as the two questions together in Fig. 7, but the survey of Fig. 8 was done shortly after the last lab ended and students answered this question without preparation, in contrast with the Fig. 7 questions of a graded “Big” quiz. Interestingly, almost the same percentage of students (72.7%) answered correctly question #3 in Fig. 8 as in the “Big” quiz, but 27.3% did not know the answer at all. At least partially, these students answered questions after preparing for the “Big” quiz (Fig. 7).

Fig. 8

Survey # 1 of OPT 204 students: a list of questions (Q) (see also Fig. 9).

Fig. 9

Survey # 1 of OPT 204 students. Four histograms of percent of students answering each of four questions of Fig. 8: (a) Q1. Selection of a future career; (b) Q2. Interest in nanotechnology; (c) Q3. Remembering nanoobjects and nanodevices from the labs; and (d) Q4. Thinking about a career in nanoscience/nanotechnology.

The second survey, with 23 students, was devoted to self-efficacy and students’ expectations of the work environment in the field of nanotechnology. The results of this class with only two 15-mins nano-mini-labs are different from those of the Nanometrology Laboratory class. Two questions from this survey are shown in Fig. 10. From this survey, only 52.2% of students are confident that they will succeed. Some of them suggested further learning in this field. 39.1% are not confident, and 8.7% suggested that to be confident they will need to take more classes on nanotechnology. Answering the second question about the work environment, 30.4% of students prefer a lab environment, 2% modeling, 2% both laboratory and modeling, and 52.2% of them are not sure what their work environment will be. The results of the Fig. 10 survey show the necessity for including information about real-world industrial and research environments in the field of nanotechnology within this class format on optical sources and detectors. Yet, the format of this class with four labs and seven lectures and its assignments is accepted by the students. For instance, here is an excerpt from an e-mail of a recent student:

Fig. 10

Survey #2 of OPT 204 students: a list of questions. The results of this survey are discussed in the text of this paper.

6.1.

Hybrid Teaching in Small Lab Rooms: High-Quality Zoom Recording of Upper-Division Labs

The requirement of a 1.5-m social distance permitted only one student and a TA to be in one laboratory room simultaneously, even with personal protective equipment. Recent research showed that, upon exhalation, a coronavirus may survive in the air in aerosols^58,59 for up to 9 h.⁵⁸ This is why in fall 2021 and the spring of 2022, an air purifier (Blue Pure 211*) with a HEPA particle filter for $\sim 500$ sq. ft room was used during all advanced lab courses. Three “in-person” scheduled lab attendants worked 1/3 of each lab time (usually 3 h) in the lab and 2/3 of each lab time remotely through Zoom.

The quality of video recording was very important, especially because one-half of two lab classes and the entire third lab class required darkness during measurements. The dynamic range of the Marshall Electronics CV610-UB video camera with remote control [see Fig. 11(a)] permitted us to show all details of the lab experiments in darkness to remote students and to record videos of each lab session. The Jabra Speak 710 microphone is shown in an insert of this figure. Remote control of the Marshall camera permits not only showing the whole setup but also focusing on its particular component. In many cases, an iPhone was used for Zoom recording even smaller details [Fig. 11(b)]. Usual webcam cameras [Fig. 11(c)] have no required quality of video and a necessary dynamic range for Zoom video recording, especially in darkness. Figure 12 from a recorded Zoom video by the Marshall camera shows all details of single-photon interference experiments in spite of darkness in a laboratory.

Fig. 11

(a) The Marshall Electronics CV610-UB video camera with remote control with a Jabra Speak 710 microphone; (b) an iPhone is widely used to record small details of the experiments; and (c) a webcam video camera does not provide the required quality of Zoom videos of lab experiments, especially right after turning off the lights in the room.

Fig. 12

(From a recorded Zoom video by a Marshall video camera). A single-photon interference lab experiment recorded in the darkness. An inset shows the power meter readings immediately after the lights were turned off.

All lab sessions were recorded, as was communication with remote students during the labs, and all videos were uploaded to Blackboard through Panopto. Blackboard is a virtual hub for student services that provides access to online course materials, grades, organizations, accounts, and many other academic and campus services. Panopto is a software that provides lecture recording, screencasting, video streaming, and video content management. All pictures of the experiments in this section are screenshots from Panopto of recorded Zoom movies uploaded to Panopto.

An option for “screen sharing” in the Zoom software facilitates participating in the experiments of remote students. See, for instance, Fig. 13 from Panopto of AFM imaging of the topography of a plasmonic nanoantenna array metasurface. In addition, a Zoom insert at the right top corner of this screenshot shows (from top to bottom) a compact AFM with a controller, a student in the lab (with a mask and a protective plastic shield), and two other students taking the lab remotely and waiting for their time in the lab.

Fig. 13

(From a recorded Zoom video with screen sharing). A user interface of an AFM Easyscan 2 (Nanosurf). An insert from a Zoom software shows an AFM, a student in the lab, and two remote students.

The most challenging labs during the pandemic years were project-oriented labs with the purpose of students’ immersion in discovery-oriented environments, in which the results of their work are initially unknown to both the students and the instructor but are of interest to stakeholders in the broad scientific community^52,53 (labs of the OPT253/OPT 453/PHY434 and OPT 254 classes in the author’s research laboratory with complex equipment). These 1.5 to 3 h/week “open-end”^52,53 projects last 4 to 5 weeks for each of several groups of three students, with the discussion of results in weekly lectures with all students in the class. Switching to hybrid teaching, in the pandemic, in the labs with the single (antibunched) photon source generation and characterization unit (see Fig. 14), five different monitors were used simultaneously in Zoom in a lab room with switching monitors using a “pin” option, for Zoom video online in real time with the recording. A host computer for Zoom, an iPhone, and a Marshall camera, as well as two lab computers connected with devices for sharing their screens with data (single-emitter fluorescence imaging/antibunching correlation measurements) and an EM-CCD camera for spectral measurements, were used during this lab. Owing to the Marshall camera dynamic focus, either the whole setup [Fig. 14(a)] or an oil drop on the microscope objective can be viewed in close-up [Fig. 14(b)]. The insert shows a recording by an iPhone at some position not accessible by the Marshall camera. Demonstrating research experiments in real time while directing the regime of the video production, wearing a respirator, and constantly speaking with the students through the Jabra microphone to increase students’ engagement constitutes a less than the optimal form of professional growth. However, real-time and instant-feedback communication with remote students through Zoom is a reward to be cherished. One of the students took this research-level lab while residing in Vietnam, and another logged in from Pakistan; however, all of these students were immersed in a real research environment, learning what it means to do research with unknown results but with the possibility of discovery.

Fig. 14

(From a recorded Zoom video by a Marshall video camera). Remote teaching of the research-oriented lab at the single (antibunched) photon generation and characterization unit. (a) A confocal fluorescence microscope for single-emitter fluorescence and a Hanbury Brown and Twiss correlator (taught by Lukishova). (b) Dropping an index-matching oil on a microscope objective. An insert from a Zoom video frame recorded by an iPhone shows the same sample table with a different view.

Some advanced labs were held at the URnano facility’s TEM and SEM. URnano computers cannot be used for Zoom—not all screens can be shared. In this case, we used either the Marshall camera or an iPhone to record the URnano computer monitors during a scheduled class time.

6.2.

Evaluation of Students’ Knowledge via Zoom and Lessons Learned

One of the main problems in online instruction is how to administer exams while suppressing cheating, minimizing students’ anxiety, and preserving their privacy.⁴⁹ In the Physics Today paper,⁴⁹ several examples of remote exam practice are outlined. In the three lab classes mentioned in the preface to the current Sec. 6, in the pre-pandemic years, every group of three students scheduled for their lab was required to answer individually several questions of a graded 10-min-written quiz in the presence of a TA as their proctor. In the middle and at the end of a semester, one to three other “Big” written quizzes with up to 25 questions were included with proctoring. Trying to find the best solution for the remote exams in a pandemic, we declined as unpractical any proctoring software described in Ref. 49 and selected a practice similar to that of Carl Wieman of Stanford University:⁴⁹ open book route. To understand if the students really learned the course, additional, graded 15 to 20 min oral “Big” quizzes with the students divided into several groups between TAs and a professor were scheduled (at a definite time for each student) after their written “Big” quiz. The short quizzes before each lab also became “open book,” and the students were required to upload their answers before the labs, but during the online lab sessions, TAs asked each student the quiz questions, and in the case of failing to answer, the grade for the written quiz was reduced. A very important lesson that we learned from this successful practice for avoiding cheating is that a combination of both written and oral exams works, and we continue to use this practice since all classes at the UR returned to the “all students in-person” requirement. We only replaced open book written exams with proctoring. Cheating becomes evident during the oral exams, even with fewer questions and a shorter time. Surprisingly, our practice shows an interesting observation: sometimes students demonstrate much better knowledge in their oral exams than in open book written exams.

Learning outcomes from our experience in pandemic with advanced, upper-division lab classes demonstrated that a hybrid format of recording real-time lab sessions and communicating with students via Zoom has advantages in students’ assignment preparation. Grading of all lab reports and quizzes showed higher grades of assignments and final grades in comparison with the pre-pandemic years when Zoom recorded videos of lectures and lab sessions had not yet been used. For instance, we compared an average “Big” quiz grade in 2019 (90.66 points) and 2021 (94.5 points) (see Fig. 15) and average final grades in 2019 (90.47%) and 2021 (95.9%) (see Fig. 16) for OPT 204 with 35 students in 2019 and 33 students in 2021. The impact of the online videos on students’ learning was thoroughly investigated in Ref. 60:

Fig. 15

(From Blackboard). Statistics of the OPT 204 class grades for a final “Big” quiz (maximum 100 points). (a) For a pre-pandemic year (2019) and (b) for a pandemic year (2021).

Fig. 16

(From Blackboard). Statistics of the OPT 204 class final grades (maximum 600 points, 100%). (a) For a pre-pandemic year (2019) and (b) for a pandemic year (2021).

We would like to add that, despite a lack of “hands-on” experience for remote students, for instance, in fusion splicing of the optical fibers, showing online struggles of “in-person” students with detailed, high-quality real-time videos (see Fig. 17 from a video screenshot) permitted them to learn more about this procedure in comparison with pre-pandemic years students of this class. In addition, following the needs of remote students, a separate educational video was prepared in the optics teaching labs, so remote students’ learning needs forced us to significantly improve course materials.

Fig. 17

(From a recorded Zoom video by an iPhone camera.) Fusion splicing of the optical fibers during a remote lab. A Marshall camera positioned on a cart in a small room did not permit recording of this delicate procedure in detail.

Another lesson learned was the importance of socialization for remote students, even through Zoom: students with up to a 13-h time shift voluntarily attended the labs at a local night time and refused any offer to watch the recorded lab sessions without real-time feedback and communication with other students.