Study on Nonlinear Absorption Effect of Nanosecond Pulse Laser Irradiation for GaAs

2016 ◽  
Vol 16 (4) ◽  
pp. 3895-3898
Author(s):  
Wenjun Sun ◽  
Zhongyang Liu ◽  
Haijiao Zhou
Keyword(s):  
Laser Irradiation ◽  
Power Density ◽  
Pulse Laser ◽  
Free Carrier ◽  
Semiconductor Material ◽  
Photon Absorption ◽  
Free Carrier Absorption ◽  
Pulse Laser Irradiation ◽  
Carrier Absorption ◽  
Nanosecond Pulse Laser

In order to research nonlinear absorption effect of pulse laser irradiation for GaAs, a physical model of Gaussian distribution pulse laser irradiation for semiconductor material was established by software COMSOL Multiphysics. The thermal effects of semiconductor material GaAs was analyzed under irradiation of nanosecond pulse laser with wavelength of 1064 nm. The radial and transverse temperature distribution of semiconductor material GaAs was calculated under irradiation of nanosecond pulse laser with different power density by solving the thermal conduction equations. The contribution of one-photon absorption, two-photon absorption and free carrier absorption to temperature of GaAs material were discussed. The results show that when the pulse laser power density rises to 1010 W/cm2, free carrier absorption played a leading role and it was more than that of one-photon absorption of material. The temperature contribution of two-photon absorption and free carrier absorption could be ignored at laser power density lower than 108 W/cm2.The result is basically consistent with relevant experiments, which shows that physical model constructed is valid.

TUNABLE ASYMMETRIC FANO LINESHAPES IN SILICON-BASED MICRORING RESONATORS WITH FEEDBACK

2011 ◽  
Vol 20 (03) ◽  
pp. 357-366 ◽  
Author(s):  
SANTHAD PITAKWONGSAPORN ◽  
SURASAK CHIANGGA
Keyword(s):  
Continuous Wave ◽  
Operating Regime ◽  
Free Carrier ◽  
Photon Absorption ◽  
Microring Resonators ◽  
Free Carrier Absorption ◽  
Coupling Coefficients ◽  
Linear Absorption ◽  
Carrier Absorption ◽  
Silicon Based

We theoretically examine the Fano lineshapes of silicon-based compound microring resonators consisting of a single resonator channel dropping filter linked to a loop as a feedback structure. All possible optical effects for the continuous-wave operating regime, such as linear absorption or scattering, two-photon absorption, free-carrier absorption and dispersion, thermo-optics, are simultaneously considered. We show that sharp Fano resonances can be tuned by variation in the coupling coefficients, length of feedback loop, effective free carrier lifetime and the temperature inside the device. Tunable Fano lineshapes open up opportunities for applications in sensing, computing, and communications.

scholarly journals Ultrafast Broadband Nonlinear Optical Response in Co-Doped Sb2Se3 Nanofilms at Near-Infrared

2021 ◽  
Vol 8 ◽  
Author(s):  
Di Sun ◽  
Yu Fang ◽  
Xiaoyan Yan ◽  
Wen Shan ◽  
Wenjun Sun ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Near Infrared ◽  
Optical Response ◽  
Free Carrier ◽  
Nonlinear Optical Response ◽  
Photon Absorption ◽  
Free Carrier Absorption ◽  
Ultrafast Carrier ◽  
Carrier Absorption ◽  
Co Doped

Transition metal-doped Sb2Se3 has become a heated topic caused by the strong nonlinear optical response and the ultrafast response time at high laser excitation. In this paper, the Co-doped Sb2Se3 with different doping amount (0.5, 1.0, and 1.5 W) nanofilms were prepared by magnetron sputtering technology, and the nonlinear behavior of Co-doped Sb2Se3 nanofilms at near infrared were systematically studied. The results of the femtosecond Z-Scan experiment indicate that the Co-doped Sb2Se3 nanofilms exhibit broadband nonlinear response properties owing to the free carrier absorption, the Kerr refraction, the two-photon absorption, and the free carrier refraction. The nonlinear absorption coefficients of Co-doped Sb2Se3 nanofilms are from 3.0 × 10−9 to 2.03 × 10−8 m/ W under excitation at 800, 980, and 1,030 nm, and the nonlinear refractive index of the Co-doped Sb2Se3 nanofilms is from 4.0 × 10−16 to -3.89 × 10−15 m2/ W at 800, 980, and 1,030 nm. More importantly, Co-doped Sb2Se3 (1.5 W) nanofilm exhibits ultrafast carrier absorption (<1 ps) and a stronger transient absorption intensity of ΔOD > 6.3. The Co-doping content can controllably tune the crystalline degree, the ultrafast carrier absorption, the intensity of the reverse saturation absorption, the broadband nonlinear optical response, and the carrier relaxation time of Co-doped Sb2Se3 nanofilms. These results are sufficient to support their applications in broadband nonlinear photonic devices.

Free Carrier Absorption in P-Type Epitaxial Si and GaAs Films for far-Infrared Detection

1997 ◽  
Vol 484 ◽  
Author(s):  
A. O. U. Perera ◽  
W. Z. Shen ◽  
M. O. Tanner ◽  
K. L. Wang ◽  
W. Schaff
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Far Infrared ◽  
Infrared Region ◽  
Free Carrier ◽  
Photon Absorption ◽  
Free Carrier Absorption ◽  
Absorption Data ◽  
Carrier Absorption ◽  
P Type

AbstractWe report the investigation of free-carrier absorption characteristics for epitaxially grown p-type thin films in the far-infrared region (50 ∼ 200 μm), where homojunction interfacial workfunction internal photoemission (HIWIP) detectors are employed. Five Si and three GaAs thin films were grown by MBE over a range of carrier concentrations, and the experimental absorption data were compared with calculated results. The freehole absorption is found to be almost independent of the wavelength. A linear regression relationship between the absorption coefficient and the carrier concentration, in agreement with theory, has been obtained and employed to calculate the photon absorption probability in HIWIP detectors. The detector responsivity follows the quantum efficiency predicted by concentration dependence of the free carrier absorption coefficient.

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