Optical Double-Photon Absorption in CdS
Abstract
Observations have been made of the two-photon excitation of an electron from the valence to the conduction band in CdS (Eg=2.5 eV) using a pulsed ruby laser (ℏω=1.78 eV). The radiative recombination emission from exciton and impurity levels subsequent to the simultaneous absorption of two quanta of ℏω=1.78 eV was observed as a function of laser intensity and compared to the emission excited by single-quanta absorption for photons of ℏω>Eg. It was found that the intensity of the recombination radiation is proportional to I0n for single-quanta excitation and I02n for double-quanta excitation, where I0 is the excitation intensity and n is a constant which differs for different groups of emission lines. The observed cross section for double-quanta excitation is compared with theory utilizing the band parameters of CdS.
- Publication:
-
Physical Review
- Pub Date:
- April 1964
- DOI:
- 10.1103/PhysRev.134.A499
- Bibcode:
- 1964PhRv..134..499B