- Flexible beat detection units
- Designed for use with DFC and DL pro
- Stable and compact
TOPTICA's beat detection consists of two flexible modules: DFC BC and DFC MD. Separating beam combination and beat detection into two units allows for placing them at different locations. The DFC BC and DFC MD units are specifically designed for a combination of the DFC with TOPTICA's DL pro tunable diode laser series, but can also be used with other cw lasers.
The DFC BC (beam combiner) spatially overlaps the DFC output with a cw laser. The relative intensities between both beams can be adjusted internally. If a fixed splitting ratio is acceptable the DFC BC can be replaced by an all-fiber combiner. The unit can also be used individually as an ultra-stable combiner and fiber coupler for any pair of laser beams.
Fiber beam combiner for DFC and cw-laser, 980 nm, 1030 nm, 1300 nm, 1550 nm.
The DFC MD (monochromatic detector) detects a beat-note between the DFC and a cw laser with the highest possible signal to noise ratio. Using a grating-based adjustable filter with a bandwidth of 10 GHz and a tuning range of several 10 nm, it filters a narrow spectral component of the combined cw laser and DFC. The unit also includes a low-noise photodetector and amplifier to detect the RF beat-note signal. It enables three different operation modes:
- Measurement of the beat frequency using the beat monitoring unit of the DFC CORE module
- Active locking of the cw laser to the DFC (requires additional locking electronics for the cw laser)
- Locking of the DFC to the cw laser (requires DFC CORE+ version)
The photodetector can be detached from the DFC MD unit to convert it into a monochromator serving as narrow band frequency filter. The output of the monochromator can be fiber-coupled or attached with slits of different sizes defining the filtering bandwidth.
DFC BC DFC MD Inputs 1. Frequency comb: Fiber-coupled (FC/APC fiber coupler included), > 0.25 mW/nm recommended
2. cw laser > 100 μW recommended, 1 mW ideal
(fiber-coupled, fiber coupler included)
Frequency comb + cw laser: Fiber-coupled
(fiber coupler included)
Outputs 1. Frequency comb + cw laser: Fiber-coupled,
(fiber coupler and SM/PM fiber included)
2. cw laser: Free beam (fiber coupling optional)
RF signal, amplified for use with mFALC Wavelength 420 nm - 2200 nm Spectral width of
approx. 50 nm (depends on central wavelength) 50 nm (depends on central wavelength) Filter element n.a.
- 10 GHz bandwidth grating (other bandwidths on request)
- Optical resolution > 50.000
- Tuning via manual adjustment of µm-screw incl. scale reading
- Tuning resolution < 1 GHz (typ.)
Dimensions (H x W x D) 49 x 100 x 100 mm 64 x 60 x 120 mm
- Scientific Article: M. Collombon et al., Phase transfer between three visible lasers for coherent population trapping, Optics Letters Vol. 44, Issue 4 (2019)
- Scientific Article: A. Liehl et al., Ultrabroadband out-of-loop characterization of the carrier-envelope phase noise of an offset-free Er:fiber frequency comb. Optics Letters Vol. 42, Issue 10 (2017)
- Scientific Article: T. Puppe et al., Characterization of a DFG comb showing quadratic scaling of the phase noise with frequency, Optics Letters Vol. 41, Issue 8 (2016)
- Scientific Article: G. Krauss et al., All-passive phase locking of a compact Er:fiber laser system, Opt. Lett., 36, 540 (2011)
- Scientific Article: D. Fehrenbacher et al., Free-running performance and full control of a passively phase-stable Er:fiber frequency comb. Optica Vol. 2, Issue 10 (2015)
- Scientific Article: R. Kliese et al., Difference-frequency combs in cold atom physics, arXiv:1605.02426v1 (2016)
- Scientific Article: D. Brida et al., Ultrabroadband Er:fiber lasers, Laser & Photonics Review 8(3) (2014)
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