This PDF file contains the front matter associated with SPIE Proceedings Volume 12569, including the Title Page, Copyright information, Table of Contents, and Conference Committee listings.

We perform infrared imaging upconversion of a coherent signal at 1550 nm using a spatially shaped pump. Our experimental and simulation results demonstrate that the use of a uniform pump beam (flat-top) can enhance the number of spatially resolved elements due to the better spatial distribution of the energy compared to the gaussian beam for which the finite transverse aperture of the crystal limits the suitable waist without being cut by the crystal. With a 1 × 1.5 mm² aperture crystal, we could convert 170 modes with a 400 μm radius flat-top pump against 156 with a 330 µm radius gaussian pump.

Digital holography is an imaging technique that enables a 3-dimensional reconstruction of the electromagnetic field scattered by an object in both amplitude and phase. We demonstrated its use in microscopy in linear regime for the full 3-D mapping of the field scattered by single nanostructures such as nano-antennas and near-field probes. Holography is a technique based on interferences, which can be obtained at the laser illumination wavelength, but also with Second Harmonic Generation (SHG), since the latter is produced in a coherent process. Here, we describe the development of a harmonic holographic microscope for single-shot mapping of the second harmonic 3D radiation pattern near samples with nonzero second harmonic susceptibilities. The knowledge of the scattered field (amplitude and phase) in a given plane (that of the camera) allows its reconstruction in any other plane using e.g. the angular spectrum representation of the optical fields, and assuming propagation in homogeneous media, a process called 3D numerical back-propagation [6]. In addition to providing 3D reconstruction, thus enhancing the imaging capabilities beyond those of back focal-plane imaging, the harmonic holography microscope also benefits from an amplification effect since the signal from the sample is multiplied by an intense reference in the interference term, making the method particularly well suited to measure the weak SHG signals. After a first validation on dielectric samples made of nonlinear micro-crystals and cornea collagen, we are implementing the technique to obtain SHG fields radiated by plasmonic nano-antennas.

We study the effects of annealing temperature on oxide charge trapping near the SiO₂/Si interface using time-dependent second harmonic generation (TD-SHG), which is sensitive to charge separation near the interface. The TD-SHG signals are measured in plasma enhanced tetraethyl orthosilicate (PE TEOS) and high density plasma (HDP) oxide films deposited on silicon, respectively, which are typically used as intermetal dielectric (IMD) layers in 3D NAND. After annealing at temperatures ranging from 550 °C to 850 °C, the initial slopes of the TD-SHG signals at t=0, related to the charge trap density, decrease with increasing annealing temperature for PE TEOS, while the signals from HDP oxides show relatively flat curves independent of temperature even in the as-deposited state due to the reduced charge traps. The direction of the interfacial electric field resulting from the charge separation can be interpreted from the sign of the measured slopes. In PE-TEOS oxides annealed above 800 °C, the slope changes to the opposite sign, indicating the dominance of negative charges rather than positive charges. The observed TD-SHG results support previous suggestions that the electron trapping occurs in the carbon-related center of TEOS and appears to be dominant after high temperature annealing.

Photonics and spintronics represent a great promise to overcome the fundamental limits of electronics since light and spins are simultaneously much faster and less dissipative of electrons. In this framework, the quest for energy-efficient data processing and storage functionalities led great attention to the field of femtomagnetism, the study and control of magnetism using ultrashort light pulses. However, our knowledge of magnetic phenomena and ultrafast light-matter interactions in nanoscale magnetic materials is extremely limited. In this work, we introduce a time-resolved magnetooptical pump-probe spectroscopy scheme enabling to access both the thermal and nonthermal spin (and charge) dynamics with sub-15 fs temporal resolution. We test the capabilities of our system on archetypical magnetic and magnetoplasmonic materials, such as Ni thin films and Ni nanodisks.

We propose and theoretically analyze a novel device with a simple architecture for high power mid-wave and long-wave infrared beam generation by employing a realistic model that takes the diffraction of the beams into account. The device is a seeded optical parametric generator (OPG) based on an aperiodic orientation-patterned GaAs (OP-GaAs) grating in which two optical parametric amplification (OPA) processes, OPA1 and OPA2, are simultaneously quasi-phase-matched along the full length of the crystal. When pumped by a high-repetition-rate nanosecond-pulsed pump laser operating at 2.1 μm and a low-power continuous-wave seed source at a wavelength of 2.74 μm (signal), OPA1 in this crystal generates a long-wave infrared beam output at a wavelength of 8.8 μm (idler) whose power conversion efficiency is enhanced by means of OPA2 compared to what is achievable with a single OPA process. OPA2 occurs as signal photons are down-converted to idler photons and difference-frequency (DF) photons at a wavelength of 3.98 μm. These wavelengths have important applications in the fields such as infrared laser projector technologies, countermeasures against heat seeking missiles, remote sensing, and spectroscopy.

Within the last decade, research and development in the field of silicon microring resonators have been accelerated due to their potential in a wide range of applications. In this study, we experimentally characterize the selfpulsing dynamics in active silicon ring cavities under the effects of varying the optical power, detuning, and free-carrier lifetime. Self-pulsing is measured by coupling a single laser source into the microring resonator’s input port. The light collected from the output grating is fiber coupled and sent to a photodetector, oscilloscope, power meter, and optical spectrum analyzer (OSA) for both time and frequency domain measurement.

In this work, we analyze the operating speed of photonic integrated circuit (PIC) with microring resonator using the transfer function model. The transfer function is obtained from single microring resonator and waveguide, further modified for complex circuits with multiple microring resonators and waveguides. The model was run in Matlab without running time, while indicating the influence of change in PIC parameters to the output. The simulation showed large coupling coefficient (k<0.2) and small radius (R< 8 um) of microring increases operation speed to 30 Gbps, but decreases quality factor below 1500. The model is recommended for designing PIC at early stage with small time.

The present contribution provides a link between optical pumping with polarized light and polarized optical injection in a Quantum-Dot (QD) Vertical-Cavity Surface-Emitting Lasers (VCSEL). Based on the sensitivity of the QD spin-VCSEL to the stability state before the injection and the rich dynamic behaviour induced by optical injection we perform an analysis of optimized parameters for the demonstration of extended chaotic regions. The proposed scheme aims at ultrafast random bit generation (RBG) reducing the complexity of wellestablished systems based on VCSELs to generate high-quality chaos signals. Our investigations reveal that inside these regions an enhancement of chaotic bandwidth up to 50 GHz can be achieved, exceeding the stateof-the-art performance of conventional VCSELs under continuous wave (CW) optical injection. We show that in addition to exhibiting enhanced polarization chaos, QD spin-VCSELs enable 240 Gbit/s RBG thus allowing future exciting routes for cryptography and secure communications.

Grating is the most suitable for the excitation of the SPP because the grating coupling is more compatible than prism coupling for active PIC devices. But traditional gratings are not able to selectively excite SPP waves at single interfaces of the metallic waveguides. Traditional gratings usually excite SPP wave at the interface where they are or, for thin metallic nanostrips, at both interfaces. But the reduction of the thickness of the metal layer in the presence of a grating has the handicap of increasing the tunnelling of the light towards the substrate, increasing the losses and reducing the coupling efficiency. Through numerical simulations, I optimized the effective parameters for the coupling of the SPP waves, such as the angle of incidence, the thickness of the metal layer in the grooves of the buried lattice and in the upper cover, as well as the width and depth of the grooves. As a result of the optimization process, the efficiency of light coupling in the SPP wave increased at the lower interface with the substrate and the transmitted tunnelling light was effectively suppressed compared to an equivalent conventional lattice. The attenuation of the transmitted tunnelling light favours the use of SPP for a nonlinear medium.

Light confinement in the nanoscale regime has opened new doors to the miniaturization of optical materials required for future integrated photonics. Recently, Tamm Plasmons (TP) have attracted research interest as they possess various advantages over conventional surface plasmons. They are characterized by sharp resonances in the transmission spectrum and a low degree of loss, making them ideal and versatile platforms for nonlinear applications. In this work, we report the enhanced nonlinear response of gold@carbon (Au@C) core-shell nanostructures aided by a TP cavity. The spacer layer containing Au@C is sandwiched between gold film and a DBR made of TiO₂ and SiO₂ layers. The photonic bandgap of the DBR is centered around 534 nm, and the final structure is characterized by a prominent transmittance peak around 532 nm, indicating the TP cavity mode. The observed TP mode is sufficiently large to induce nonlinear effects at low input intensities. This is confirmed by the open aperture z-scan results, which show a decreased transmittance at the focus characteristic of Reverse Saturable Absorption (RSA) behavior, which becomes steeper for the TP cavity structure compared to the bare Au@C core-shell reference film. The effective nonlinear absorption coefficient obtained for the TP structure is 37 times larger than the reference film containing the core-shell nanoparticles. This giant enhancement in the absorptive nonlinearity arises from the enormous energy concentrated in the spacer layer due to the presence of localized TP mode allowing stronger light-matter interaction.

In recent years whispering gallery mode (WGM) resonators have attracted interest due to their various potential passive (filters, resonators, sensors) and active (lasers, four-wave mixing) applications. By choosing an appropriate material with very low absorption, and fabricating a very smooth surface, WGM resonators can reach ultra-high quality (Q) factors. Additionally, the surface of the WGM resonator can be functionalized with nanoparticles or nanomaterial layers, which can enhance optical properties. Recently, we have been interested in the functionalization of the WGM resonator surface for active applications. WGM resonators are suitable for nonlinear optical interactions due to their ultra-high Q factors, significantly lowering necessary pumping power. WGM resonators can be used to generate optical frequency combs (OFCs), which have many applications in optical clocks, spectroscopy, and communications. After coating WGM resonator with quantum dots, besides the OFC generation, we have observed the third harmonic generation. Functionalization with erbium ions leads to the observation of lasing.

Voigt effect is a nonlinear magneto-optical phenomenon originating from the rotation and ellipticity of linearly-polarized light as it travels in optically active media. In this study, the detailed features and capabilities of a newly developed ultra-sensitive Voigt rotation device consisting of a GaN-based diode emitting light of wavelength range 400 – 480 nm as the light source. A transverse 1 T magnetic field is used to trigger the optical media response. A sensitive and fast semiconducting detector is employed to detect the finest rotation in light polarization. The detector is also coupled with an electronic circuit board which is configured to record changes in the polarization direction of the transmitted light relative to the reference polarizer, in addition to measuring the absolute magnetic field strength. The device sensitivity and modes of operation will also be presented. Moreover, a theoretical model to simulate polarized light transmission through optically active media will be presented and compared with experimental results.

We present a comparative study of supercontinuum generation in sapphire, yttrium aluminium garnet (YAG) and potassium gadolinium tungstate (KGW) crystals with 210 fs, 1030 nm pulses from an amplified Yb:KGW laser. We demonstrate that KGW crystal has the lowest supercontinuum generation threshold, negligible bulk heating due to low nonlinear losses and exhibits long-term damage-free operation at 2 MHz repetition rate without any need for translation of the crystal. Our results prove that KGW crystal is an excellent nonlinear material for high average power infrared supercontinuum generation and for seeding high repetition rate fundamental harmonics-pumped ultrafast optical parametric amplifiers.

The development of new services and the expansion of legacy services are constantly increasing the demands on access networks. Passive optical networks can meet these increasing demands by develop a new standard and improve existing optical networks. Currently, next generation passive optical networks provide sufficient transmission capacity while allowing legacy standards to coexist. One way to improve already deployed optical networks is to use higher order modulation formats together with coherent detection and digital signal processing. Phase-based modulation formats can provide sufficient performance improvement by phase noise compensation. First implemented phase noise algorithm exhibits potential improvement in bit error rate more than 6 orders of magnitude for 4-QAM with compared to QPSK and DQPSK. The second algorithm significantly achieves improvement in bit error rate but has comparable results in compensating for phase noise according to the number of symbols in constellation diagram.

A physical model of compact generator of infrared surface plasmon polaritons based on a planar waveguide structure to produce short pulses with a controllable repetition rate is proposed. The pulse generation is produced by modulation instability of continuous surface plasmon polariton waves in a film structure with graphene sheets (two graphene sheets spatially separated by a dielectric layer).

Harmonically mode-locked (HML) fiber lasers delivering pulses with pulse repetition rate (PRR) in the GHz range have become a valuable alternative to semiconductor and solid-state lasers ensuring high beam quality, reliability, userfriendly light output, inherent to laser configurations in all-fiber format. The main drawback of HML laser technology is the noise-induced irregularities of the time interval between pulses known as the HML timing jitter. Ensuring low-level supermode noise and precise pulse repetition rate tuneability in all-fiber-integrated harmonically mode-locked laser sources establishes a new level of their versatility and extends areas of their applications. We report on new techniques enabling both the mitigation of supermode laser noise and highly precise setting of the PRR in a soliton fiber laser harmonically mode-locked by nonlinear polarization evolution. The principle of operation relies on resonant interaction between the soliton pulses and a narrow-band continuous wave (CW) component cooperatively generated within the same laser cavity.

Brillouin amplification, the most prominent effect implemented with Brillouin dynamical gratings (BDG), enables exponential narrowband gain that is Stokes-shifted by some value in the GHz range. In this process, the interaction of the counterpropagating pump and Stokes waves through a BDG they produce causes an increase of the Stokes-shifted wave amplitude and decrease of the pump wave amplitude during their propagation through the fiber. Here, we report on a similar effect that could be implemented in rare-earth-doped fibers with the population inversion dynamical gratings. The effect is the most pronounced in a bidirectional rare-earth-doped optical fiber amplifier. Two monochromatic optical signal waves are introduced into the fiber from opposite ends and experience amplification (if the fiber is pumped) or attenuation (if the fiber is unpumped) as they propagate through the fiber. The signal waves are coherent on a sub-kHz level and slightly detuned. In terms commonly accepted in stimulated Brillouin scattering these counterpropagating signal waves correspond to what is referred to as "pump" and "Stokes" waves. However, in contrast to the Brillouin process, their interference inside the rare-earth-doped fiber creates not acoustic, but the population inversion dynamical gain grating. Then interaction between the signal waves and created population inversion dynamical gratings cause a strong power transfer from one signal wave to another.