CHARM Active Coherence Stabilization
Dec 2011TOPTICA Photonics Inc.Request Info
VICTOR, N.Y., Dec. 7, 2011 — Toptica Photonics Inc. has expanded its BlueMode diode laser family product portfolio to include GreenMode and RedMode. The new models deliver high power and high coherence from a single diode across the visible spectrum. All models are now available with proprietary CHARM (coherence-advanced regulation mode) technology for active coherence control.
The BlueMode devices are used in inspection and metrology tasks. Researchers and engineers benefit from the combination of high power (up to 50 mW at 405 nm) and single-frequency operation.
The BlueMode wavelengths of 405, 445 and 488 nm are now complemented by the GreenMode (515 nm, 25 mW) and RedMode (638 nm, 30 mW and 685 nm, 25 mW) models. Blue/green wavelengths are suited for Raman spectroscopy and quantum cryptography, and red wavelengths are a common choice in interferometry. Applications requiring multiple laser lines benefit from the option of running two lasers simultaneously with the same set of driver electronics.
First-generation BlueMode lasers produced mode stability, but a change in ambient temperature, air pressure or humidity levels could lead to occasional mode instabilities and incoherent, multimode emission intervals. The company devised a new CHARM stabilization scheme to handle these challenges. CHARM uses a field-programmable gate array-based regulator to ensure continuous single-frequency operation, providing long-term laser wavelength and output power stability. Mode hops and resulting “step changes” of the laser’s power or frequency have been eliminated.
CHARM stabilization is available for all BlueMode/GreenMode/RedMode wavelengths with a computer-controlled laser system that uses a few simple software commands. All of the lasers feature an integrated isolator for optical feedback protection and can be equipped with proprietary Fiberdock for efficient fiber coupling of, typically, >60% into a single-mode fiber.
Features include a linewidth of <5 MHz, coherence length of >25 m, continuous mode-hop-free operation with CHARM stabilization, and long-term wavelength stability of <0.5 pm/h.
Additional applications include holography and photonic down-conversion.