Project: REal time acousto-optic based SPectrometer for femtosecond broadband and/or tunable mid InfraREd laser sources

In the "MIR Infrared Lasers" report dated September 2010, issued from Strategies Unlimited, solid growth for MIR lasers devoted to sensing and military applications is anticipated. Of particular interest is the 3-12 microns spectral range, for which emerging broadly tunable and/or multiple octave spanning spectrum laser sources along with commercially available femtosecond MIR sources exist in numerous research laboratories all around the world. A non exhaustive list of such MIR femtosecond sources is:_x000D_ -Synchronously pumped femtosecond MIR optical parametric oscillators pumped by Thulium or Chromium doped based oscillators coupled to photonic crystal fibers for supercontinuum generation in the MIR,_x000D_ -Synchronously pumped femtosecond MIR optical parametric oscillators pumped by Thulium or Chromium doped based oscillators further amplified by Holmium chirped pulse amplifiers_x000D_ -Commercial Titanium Sapphire or Ytterbium chirped pulse amplifiers coupled to optical parametric amplifiers and subsequent difference frequency generator_x000D_ -Spectral broadening techniques such as self phase modulation in rare gases pumped by the output of optical parametric amplifiers._x000D__x000D_In principle many techniques and related commercial instruments could provide for the spectrum measurement of such femtosecond based broadband or broadly tunable MIR radiations, however none of the techniques is adapted to the specific spectral characterization requirements of such sources._x000D_Commercial FTIRs scanning spectrometers which rely on mobile delay lines are not well suited for high intensity low rep rate (lower than 5 kHz) MIR femtosecond sources, since the energy per pulse may vary from one pulse to the next one, and since the FTIR technique can not discriminate such energy fluctuations. Grating based spectrometers or mini spectrometers lack the existence of affordable detector arrays when wavelengths beyond 1.7 microns are of interest, and monochromators suffers from slow scan rate, making the spectrum monitoring for high repetition rate sources unpractical. Versatite AOTF spectrometers also exist commercially, but are limited to at most 4.5 microns due to the lack of suited acoustic materials and required transducer processes and technologies, and barely support an octave spectrum._x000D_In research laboratories, a widespread technique is the frequency upconversion technique which allows, via a non linear mixing process, to upconvert the MIR spectrum in an NIR or visible spectrum easily analyszed by commercially available grating based spectrometers. However the upconversion technique relies on phase matching processes which are bandwidth limited, and are generally purposedly "home made" solutions far from being versatile enough to become a commercial product._x000D__x000D_In the RESPIRE proposal, we aim at developing and commercializing a product line of MIR AOTF based real time scanning spectrometer with ratio detection, which will overcome most if not all of the above drawbacks and limitations, and will consequently address the global MIR femtosecond laser characterization market. To this aim, Fastlite capitalizes on the output of the previously conducted MIRSA Eurostars program, which outcome has been for the development of a very unique family of high resolution Hg2Cl2 (Calomel) AOTF devices._x000D_RESPIRE will turn Fastlite's unique component technological capability in a commercial high end spectrometer system._x000D__x000D_The unique features of the AOTF MIR spectrometer are: real time readout of octave to multiple octave spanning spectra in the MIR (from 2 to 10 microns), simultaneous detection of the AOTF zero order and first order (diffracted) light beams for pulse energy discrimination, which is mandatory for accurate spectrum characterization, rapid (up to tens of kHz) amplitude modulation capabilities for signal to noise enhancement, and programmability of the spectral resolution, thus programmability of the number of points in the spectrum._x000D__x000D_The consortium is lead by Fastlite, a French R and D performing SME, which is currently the world leader in femtosecond pulse shaping through its Acousto Optic Programmable Dispersive Filter, cumulatively sold at more than 400 system units worldwide, and femtosecond pulse characterization solutions through its complete line of products implementing FROG, SPIDER, and SRSI techniques. The associated consortium P is the Photonic Institute of the Technical University of Vienna in Austria, a world renowed research laboratory for femtosecond laser technologies and related research sciences.

Acronym	RESPIRE (Reference Number: 7475)
Duration	01/10/2012 - 30/09/2014
Project Topic	We propose to develop and commercialize a product line of MIR AOTF real time spectrometers for the multiple octave spanning spectrum characterization of femtosecond MIR laser based sources.
Project Results (after finalisation)	Prototype shortwave/midwave infrared (SWIR/MWIR) and longwave infrared (LWIR) spectrometers based on a programmable acousto-optic filter has been developed and tested. The SWIR/MWIR device is based on TeO2 (paratellurite) crystal and the LWIR apparatus-- on Hg2Cl2 (calomel) crystal. TU Vienna's CO role in the project was to test the performance of these devices with tunable and fixed-wavelength laser sources.
Network	Eurostars
Call	Eurostars Cut-Off 8

Project partner

Number	Name	Role	Country
2	FASTLITE Sarl	Coordinator	France
2	Technische Universitaet Wien	Partner	Austria