The BlueMode / RedMode / Green Mode diode lasers.

The BlueMode / GreenMode / RedMode, a diode-based laser providing a stable coherence length of more than 25 m.

Nov 23, 2011
Product news

BlueMode: New Wavelengths with CHARM

TOPTICA introduces active coherence stabilization scheme

TOPTICA Photonics has expanded the product portfolio of the successful BlueMode diode laser family. The new “GreenMode” and “RedMode” models transfer the original concept – high power and high coherence from a single diode – across the visible spectrum. What’s more, all models are now available in TOPTICA’s proprietary CHARM technology, a “world’s first” technique for active coherence control.

TOPTICA´s BlueMode has rapidly gained acceptance in demanding laser-based inspection and metrology tasks. Researchers and engineers benefit from the combination of high power (up to 50 mW at 405 nm) and single-frequency laser operation, which is unmatched by any other direct diode-based source.

The established BlueMode wavelengths (405, 445 and 488 nm) are now complemented by new GreenMode (515 nm, 25 mW) and RedMode (638 nm, 30 mW and 685 nm, 25 mW) models. Blue/green wavelengths are well suited for Raman spectroscopy and quantum cryptography, whereas red wavelengths are a common choice in interferometry. Applications requiring multiple laser lines will appreciate the option of running two lasers simultaneously with the same set of driver electronics.

Even though the first-generation BlueMode lasers already outperformed the competition in terms of mode stability, a change in ambient conditions – temperature, air pressure or humidity levels –could still lead to occasional mode instabilities and incoherent, “multi-mode” emission intervals. TOPTICA’s answer is the newly designed CHARM stabilization scheme. CHARM (Coherence-advanced regulation mode) employs an FPGA-based regulator to ensure continuous single-frequency operation – and thus an excellent long-term stability of the lasing wavelength and output power. Mode-hops and resulting “step changes” of the laser’s power or frequency have thus become a hassle of the past.

The CHARM stabilization is available for all BlueMode / GreenMode / RedMode wavelengths. The laser system is computer-controlled with just a few simple software commands.

All BlueMode / GreenMode / RedMode lasers feature an integrated isolator for optical feedback protection, and can be equipped with TOPTICA´s proprietary Fiberdock for highly efficient fiber coupling (typically > 60% into a single-mode fiber).

BlueMode, GreenMode and RedMode lasers with CHARM stabilization will be demonstrated live at Photonics West, San Francisco, at the TOPTICA booth (8)717.


Key Features 

  • Up to 50 mW output power
  • Linewidth < 5 MHz, coherence length > 25 m
  • Continuous mode-hop-free operation with CHARM stabilization
  • Available wavelengths: 405 nm, 445 nm, 488 nm, 515 nm, 638 nm, 685 nm
  • Excellent long-term wavelength stability (< 0.5 pm/h)
  • Optional single-mode fiber coupling with highest efficiency (typ. 60%)


Applications

  • Interferometry and holography
  • Precision metrology
  • Raman spectroscopy
  • Quantum cryptography
  • Photonic down-conversion