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Wavelength tunable ASOPS system enabling fast aquisition spectroscopy

Developed from our proven line of Ti:Sapphire oscillators, KMLabs' Orthos is the first stand-alone wavelength tunable Asynchronous Optical Sampling (ASOPS) system in the market.

ASOPS is a technique commonly used in ultrafast pump-probe spectroscopy and terahertz time-domain spectroscopy (THz-TDS). It allows for high-speed and high-resolution time-resolved measurements without the need for mechanical delay lines. ASOSP systems use two mode-locked lasers, each operating at slightly different repetition rates: fmaster and fslave = fmaster – foffset where foffset causes the relative delay between the pump and probe pulses to automatically scan over time very quickly and precisely, as shown in the schematic below.
Orthos

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KMLabs Orthos Datasheet

 

Orthos Specifications

Center Wavelength ~ 800 nm
Tunable Wavelength Range ~ 750-850 nm
Repetition Rate ~ 93 MHz
Maximum Mode-locked Power > 500 mW at 800 nm
Pulse Duration (based on Fourier transform limit) < 15 fs
Pulse Energy < 5 nJ
Timing Jitter < 150 fs RMS
Repetition Rate Offset 1-20 kHz

 

Orthos integrates the Griffin Prime as the free-running MHz-range oscillator and the Halcyon Prime as the repetition-rate-stabilized oscillator, with a controlled frequency offset from the Griffin Prime. Both oscillators are mounted on a shared, water-cooled baseplate alongside a comprehensive set of diagnostics, including an optical coincidence detection system.

With the master laser repetition rate of 93 MHz and maximum offset frequency of 20 kHz, Orthos allows for scanning a >10 ns time delay window in an unprecedented acquisition speed, as short as 50 microseconds.

The ability to independently tune the center wavelength of each oscillator enables:

  • On-demand spectral filtering of the pump and probe beams
  • Probing specific absorption bands within materials
  • Resonant excitation of certain molecular vibrations/electronic transitions

While each oscillator’s output spectrum can be tuned in the 750-850 nm range, the possibility of coupling Orthos to an Optical Parametric Oscillator (OPO) provides an even wider wavelength tunability range on either of the pump or probe arms. Alternatively, white light continuum can be generated by pumping a nonlinear photonic crystal fiber with only a fraction of >5 nJ per pulse energy, provided by either oscillator.