Measurement of second harmonic generation efficiency of a 100 ns duration, 9.271 μm CO2 laser in orientation patterned GaAs (OPGaAs) crystal (3 mm x 7.5 mm x 39.7 mm), and in crystals of AgGaSe2, ZnGeP2 and CdGeAs2 in their largest dimensions currently available will be presented. At maximum fundamental beam fluence of 2.5 J/cm^2, 15 % conversion efficiency was achieved with the OPGaAs crystal, which was the highest among the materials studied in this work. All samples were at the ambient laboratory temperature of 23 C and the radius of the incident beam was 0.7 mm (HWe^(-1)M of intensity).
Laser damage thresholds of CdSiP2 have previously been measured at wavelengths of 1064 nm and 2090 nm using nanosecond durations lasers1,2 and at 1940 nm using a continuous wave laser3. In the continuous wave measurement attempted in the past3, the CdSiP2 sample was found to withstand an irradiance of 150 kW/cm2 for over 60 seconds without any damage to the sample, whereas earlier grown samples of CdSiP2 exposed to the same irradiance level damaged in 5 seconds or less. In that work, or in any other work to our knowledge, the samples were not exposed to millisecond or longer duration lasers at 1064 nm or 1550 nm. Because of the importance of CdSiP2 in nonlinear frequency conversion of lasers in the 1000 to 2000 nm spectral range, this study was performed to measure the damage thresholds at wavelengths in this spectral regime. Results of the damage threshold at different laser spot sizes will be presented.
μA 760 μm thick GaAs crystal was grown using HVPE. Transmission spectrum of this sample showed minimal
absorption for light having photon energy below the bandgap energy, indicating the absence of the EL2 defects
commonly found in Bridgman grown samples. Irradiance dependent absorption measured at 1.535 μm using
100 ns duration laser pulses showed increased nonlinear absorption in the HVPE grown GaAs compared to
Bridgman grown samples. The dominant nonlinear absorption process in both samples was absorption due to
free carriers generated by two-photon absorption. The HVPE grown sample showed higher nonlinear absorption
due to longer carrier lifetimes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.