Three-photon absorption spectra and bandgap scaling in direct-gap semiconductors

Abstract

This paper presents three-photon absorption (3PA) measurement results for nine direct-gap semiconductors, including full 3PA spectra for ZnSe, ZnS, and GaAs. These results, along with our theory of 3PA using an 8-band Kane model (4 bands with double spin degeneracy), help to explain the significant disagreements between experiments and theory in the literature to date. 3PA in the 8-band model exhibits quantum interference between the various possible pathways that is not observed in previous 2-band theories. We present measurements of degenerate 3PA coefficients in InSb, GaAs, CdTe, CdSe, ZnTe, CdS, ZnSe, ZnO, and ZnS. We examine bandgap, 𝐸 𝑔 , scaling using 2-band tunneling and perturbation theories that show agreement with the predicted 𝐸 𝑔 −7 dependence; however, For those semiconductors for which we measured full 3PA spectra, we observe significant discrepancies with both 2-band theories. On the other hand, our 8-band model shows excellent agreement with the spectral data. We then use our 8-band theory to predict the 3PA spectra for 15 different semiconductors in their zincblende form. These results allow prediction and interpretation of the 3PA coefficients for various narrow to wide bandgap semiconductors.

Three-photon absorption and photoluminescence in films of liquid-crystal polymers with embedded CdSe/ZnS quantum dots

“…This allows us to estimate the three-photon absorption coefficient γ, which was found to be equal to 0.17 cm 3 /W 2 . Although the QD volume fraction in the composite film is about 0.09, the γ value obtained for it is comparable with the one for bulk semiconductors (0.13-0.24 cm 3 /W 2 @ 1.54 mm for CdSe and 0.0017 cm 3 /W 2 @ 1.06 mm for ZnS (Benis et al 2020)). Thus, we can conclude that UCPL is caused by the three-photon absorption of the IR femtosecond radiation.…”

Nonlinear Optical Properties of CdSe and CdTe Core-Shell Quantum Dots and Their Applications

“…The spin-orbit coupling and intersubband transitions in quantum dots are present which may significantly alter the 3 PA process via quantum interference between different bands. To predict the spectral dependence of 3 PA of various semiconductor quantum dots it is important to account for quantum interference between different pathways and to determine the spectral shape spin-orbit coupling [98].…”

Harnessing microcomb-based parallel chaos for random number generation and optical decision making

“…Currently the microresonator in this work is critically coupled, and by using an over-coupled structure instead, higher conversion efficiency, wider optical spectrum and higher power per comb line could be obtained without degenerating the chaotic properties. Another factor which limits the chaotic bandwidth currently is the intra-cavity nonlinear loss 49 , 50 (discussed in Supplementary Note 8 ), which mainly comes from the three photon absorption and consequently free carrier absorption, leading to relatively high side lobes. This can be solved by employing an integrated PIN structure for the waveguide or working at a longer-wavelength band 51 .…”