Advances in high power semiconductor lasers such as increased spectral brightness, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime have the potential to dramatically improve diode pumped systems and enable new direct diode applications. Data are presented which demonstrate both edge emitter devices and high power surface emitting 2-dimensional arrays with internal gratings to narrow and stabilize the spectrum. Diodes with multimode high spatial brightness and high power single mode performance in the 808 and 976nm regime are described, and advances in high power arrays at eye-safe wavelengths are presented.
The plasma reflectivity edge in the infrared reflectivity spectrum measured on a narrow-gap semiconductor HgCdTe has been found to be very sensitive to the variation of carrier concentration under certain circumstance, based on which a new way of infrared modulation is studied, where the estimated modulation gain in power is impressively high. Thus, infrared radiation in far- and mid-infrared can be effectively modulated by electromagnetic waves with shorter wavelengths, and hence a less sensitive room-temperature infrared detector could be as sensitive as the existing cooled infrared detectors. The suggested new optoelectronic device, which can be termed an optical transistor, working with light beams instead of electronic currents, is quite promising for fiber communication and infrared detection as well as for investigating the relaxation processes of excess carriers in semiconductors. The detectivity for the plasma-edge detector, which is a detector equipped with an optical transistor, is calculated.
Plasma reflectivity edge in infrared reflectivity spectra measured on narrow-gap semiconductors has been found to be most sensitive to the variation of carrier concentration based upon which a new way of infrared modulation has been studied. The modulation gain in power is impressively high. Thus a less sensitive room-temperature infrared detector could be as sensitive as the existing cooled infrared detectors in detecting middle-infrared radiation. The detectivity has been calculated.