ABSTRACT
High-efficiency pulse compression has been obtained by using an externally pumped intracavity Raman oscillator. Through stimulated Raman scattering, the energy of a primary, long-pulse-duration omega(L) laser is downconverted and stored at the first Stokes frequency omega(1s) in a high-Q cavity containing the Raman medium. Then this electromagnetic energy is quickly extracted at the second Stokes frequency. This technique, which uses hydrogen gas as the Raman medium, permits a 25-nsec-duration ruby-laser pulse shortening by a factor of 12.5 with a near 50% quantum efficiency. Contrary to the case of intracavity Raman oscillators or amplifiers, this method can also be used with absorbing laser media.
ABSTRACT
High-efficiency pulse compression has been obtained by using an intracavity Raman oscillator. The energy of a primary laser stored in its high-Q cavity is extracted at the Stokes frequency by means of a Stokes laser having a high Raman gain and a low-Q cavity. This technique, using hydrogen gas as the Raman medium, permits shortening of the pulse duration of a ruby laser by a factor of 6.7 with 87% effective quantum efficiency. It would be especially useful with low-gain (alexandrite) and with short-storage-lifetime lasers.
ABSTRACT
By using a [(signal) + (noise)] - (noise) digital averaging technique in order to reduce the offset drift, an improvement of about a factor 100 has been obtained in the sensitivity of a pyroelectric detector array (PDA). Different applications of the apparatus for measurement of infrared and far-infrared beam characteristics are also presented.
