Tunable small band laser - has bandwidth of first parametric oscillator reduced using wavelength selective grating before use as injection seeding in second oscillator

摘要

The tunable, small band laser unit uses an optical parametric oscillator (10) that has a pair of mirrors (14, 16) forming a resonator and having a crystal (18) between them. The crystal can be of beta bamium borate or littium borate. The crystal may be tilted through an angle (alpha) for tuning. Two such parametric oscillators are used to generate the coherent emission and located between them is an optical system inducing a wavelength selective element (28) in the form of a reflection grating (28). The spectral bandwidth of the first oscillator is typically 0.2 to 3 nm. ADVANTAGE - Provides ease of adjustment for stable operation.