IR/MIR Wavelength Generation

Raman Shift Cell

The Raman Shift Cell is designed to convert visible or deep-red pulses generated by a dye laser to the near infrared (900 .. 1500 nm) wavelength range. Wavelength conversion is achieved by the Raman effect, i. e. Stokes-shift in a gas cell filled with either nitrogen or hydrogen under high pressure. The dye laser’s beam is focused by the specially shaped entrance window into the gas cell. In the cell, multiple orders of Stokes and Anti-Stokes beams are generated simultaneously.

After the cell’s exit window is another, adjustable lens to collimate the emerging beams. Shifted and fundamental beams are collinear and need to be separated. Two Pellin-Broca prisms are used instead of one, because the different orders are spectrally close to each other. Also, the complete length of the unit is used to have a clear separation of beams. For that reason beam input and output are on the same face of the housing. Conversion efficiency to first order Stokes is typically above 10%.

Outer dimension: 1030 mm (w) x 270 mm (d)
Laser beam height: 215 .. 234 mm

Optical Parametrical Amplifier Near-Infrared

Principles

A frequency doubled, injection seeded Nd:YAG laser is used to pump a PrecisionScan dye laser, operated in the red spectral range. The dye laser output beam and a fraction of the residual 1064 nm pulse from the Nd:YAG are mixed in a temperature stabilised LiNbO3 crystal for difference frequency generation.
The generated IR beam passes a second LiNbO3 crystal, pumped by the remaining residual 1064 nm pulse, and used as an optical parametrical amplifier. The OPA amplifies the initial IR beam, and generates signal and idler beam.