The McCumber relation can be deduced without assuming that all active centers have the same structure of sublevels. The range of validity of the McCumber relation is the same as that of the effective emission cross-section.
A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a broadband spectral range by analyzing the dependence of aberrations for different wavelengths. The principle of design is deduced in det
The scintillation indices (SIs) of Gaussian beams and vortex beams propagating in turbulent atmosphere are investigated experimentally. It is shown that with the increase of propagation distance, the SI of Gaussian beam around optical axis increases gradu
Novel construction of a resonant-cavity-enhanced photodetector (RCE-PD) with monolithic high-contrast grating (HCG) is proposed to overcome the difficulty of fabricating a high reflective mirror of RCE-PD at 1 550 nm. In this structure, HCG serves as the