WaveTrain 2

External Cavity Frequency Doubler for CW Lasers

The WaveTrain is a powerful tool for efficient and stable second harmonic generation of single-frequency continuous wave lasers like Sirah’s Matisse lasers. It is based on a low-loss, ultra compact enhancement cavity using a patented triangle-shaped ring resonator. A temperature stabilized nonlinear crystal generates the second harmonic of the enhanced fundamental radiation with very high efficiency of up to more than 35%. A Pound-Drewer-Hall locking scheme in combination with an auto-relock stabilizes the length of the resonator cavity for ultra stable second harmonic generation and widest automated tunability. The phase-matching angle of the nonlinear crystal is manually tunable over more than 50 nm.
The WaveTrain provides highest flexibility for various single-frequency laser. Two pre-mounted optics sets for quick and easy exchange cover the visible to the near infrared wavelength region. Various wavelength are accessible by exchange of pre-mounted crystal or by phase-matching angle tuning. The WaveTrain provides space for integrating various mode-matching optics within its housing.
The sealed resonator block prevents contamination of the optics and allows easy flushing of the cavity with purified air or nitrogen.

Typical Performance (LBO @ 754 nm)

WaveTrain Efficiency


Visible Near Infrared
Optic Set Range 550..780 nm 670..1050 nm
Automated Scan Range >65 GHz >40 GHz
Phase-Match Tuning 1) 2) ± 15 nm @ 660 nm ± 25 nm @ 800 nm
Maximum Scan Rate 10 GHz / s (fundamental) 10 GHz / s (fundamental)
300..600 mW 4 % 6 %
600..1300 mW 10 % 15 %
1300..3000 mW 15 % 25 %
3000..10000 mW 15 % 35 %


Pump Laser TEM00, M² < 1.1, single frequency laser
linewidth < 10 MHz, linear polarized
Ambient Conditions constant temperature in the 20..25°C range
Laboratory vibrational isolated optical table, dust-free air (flow box)
Voltage 115 V / 230 V, single phase, 50 / 60 Hz


1) phase-match tuning is defined by an intensity reduction of 50% in the SHG
2) crystal cut wavelength may vary by 1%

Optical Layout


All Dimensions in mm.
Specifications are subject to change without notice.
U.S. Patent 7,068,689

Literature & Downloads

 Datasheet WaveTrain 2