Cavity Photon Lifetime Research Articles

Gain-switched pulse generation with semiconductor lasers

The generation of picosecond optical pulses using the gain-switching method is examined using two different types of current drive at 1 GHz: short-pulse drive and sinusoidal (hard RF drive). The temporal and spectral characteristics of the resulting pulses are compared. The influence of the photon lifetime in the laser cavity has been examined for both types of drive, and it is shown that the shorter the photon lifetime then the shorter the output pulse. Simple numerical simulations are shown to give useful qualitative agreement within the limits of the model, but suggest that a limiting value of gain should be included.

Sensitive measurement of photon lifetime and true reflectances in an optical cavity by a phase-shift method

A simplified method for measuring the effective photon lifetime in an optical resonator was developed. The technique requires the passage of a modulated cw laser beam through the resonator and the measurement of the resultant shift in the phase of the transmitted intensity. The method not only permits a quick and precise measurement of the mirror reflectances, but also permits these measurements to be in situ. Such an on-the-spot evaluation capability should be extremely useful in applications ranging from the investigation of new laser systems to the development of improved optical coatings. The method is also sensitive to the effects of absorption, scattering, and transmission from elements in the cavity. Cavity losses <100 ppm were detected.

Single picosecond dye laser pulses by resonator transients

An ultrashort-cavity Rhodamin 6 G laser is pumped longitudinally by 100 psec N 2-laser pulses. The extremely short photon cavity lifetime results in picosecond dye laser pulses. The measured pulse width of 10 psec corresponds to the resolution limit of our detection system.

Test of a semiempirical equation describing laser beam divergence

A semiempirical equation describing laser beam divergence for a flat-flat laser resonator taking into consideration the resonator Q is tested. This equation describing beam divergence consists of two parts: a contribution due to diffraction and distortion in the resonator material and a term which accounts for cavity geometry and photon lifetime. Good agreement is obtained with experiment.