IR/MIR Wavelength Generation

RAMAN

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%.

Raman Shift Cell

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

DFMNIR

Infra-Red Generation

Principles

A frequency doubled, injection seeded Nd:YAG laser is used to pump the dye laser, operated in the red spectral region. The dye laser output beam and the residual 1064 nm pulse from the Nd:YAG are mixed in a temperature stabilized LiNbO3 crystal for difference frequency generation. A set of dichroic mirrors separates the generated IR pulse from the two incoming beams. Due to injection seeding, the resulting bandwidth is governed by the configuration of the dye laser resonator.

Infra Red Generation - Tuning Range

Tuning curves for mixing with approximately 500 mJ @ 532 nm; gap characteristics shown for DFM-3800-T

Infra Red Generation - Optical Layout

IR Generation - Dimensions

All Dimensions in mm. Specifications are subject to change without notice.

Literature & Downloads

OPANIR

Infra-Red Amplification

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 stabilized LiNbO3 crystal for difference frequency generation. The general IR beam passes a second LiNbO3 crystal, pumped by the remaining residual 1064 nm pulse, and used as an optical parametrical amplifier. The OPANIR amplifies the initial IR beam, and generates signal and idler beam. Due to injection seeding, the resulting linewidth is governed by the configuration of the dye laser resonator.

IR Amp - Tuning Range
Infra Red Amplification - Optical Layout

IR Amp - Dimensions

All Dimensions in mm. Specifications are subject to change without notice.

Literature & Downloads

MIR

Mid Infra-Red Generation

The Sirah mid-infra-red generation unit (MIR) is designed to generate powerful laser pulses in the wavelength range from 4.8 to 11 µm. It is operated with a Nd:YAG pump laser, a PrecisionScan dye laser, equipped with either a single or a double grating resonator with 1800 lines / mm gratings, and an optical para­metrical amplifier unit (OPANIR).

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 and a fraction of the residual 1064 nm pulse from the Nd:YAG laser are mixed in a LiNbO3 crystal for difference frequency generation. The generated IR pulse passes a second LiNbO3 crystal, pumped by the remaining 1064 nm pulse, and tuned to act as an optical parametrical amplifier. The OPA amplifies the initial IR pulse and generates signal and idler frequency. The difference frequency of these two pulses is generated in a AgGaSe2 crystal. Due to injection seeding, the resulting linewidth is determined by the configuration of the dye laser oscillator.

Mid Infra-Red Generation - Tuning Range

MIR tuning curves, when pumping with approximately 550 mJ @ 532 nm

Mid Infra-Red Generation - Optical Layout

Mid Infra-Red Generation - Dimensions

All Dimensions in mm. Specifications are subject to change without notice.

Literature & Downloads

Energy Output

DFMNIR
IR energy output at 2 µm (maximum Pyridine 1). See tuning curves for output energies at other wavelengths. Values for injection seeded pump lasers.

OPANIR
IR energy output at 2 µm (maximum Pyridine 1), combined energy of signal and idler pulse. See tuning curves for output energies at other wavelengths. Values for injection seeded pump lasers.

MIR
MIR energy output at 7.5 µm (maximum Styryl 8 in Ethanol). See tuning curves for output energies at other wavelengths.

General Characteristics