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Coherence in Control in Spectroscopy |
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TOPTICA's diode lasers span twelve
decades of coherence length. |
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Tailoring the coherence of diode lasers
The control of the coherence properties of laser light is a major success factor in many photonic applications. Whilst free-running laser diodes usually have a coherence length on the submillimeter scale, an external-cavity configuration (DL 100, DL pro) increases the coherence length by approximately six orders of magnitude. |
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For a variety of applications, however, grating feedback alone is not sufficient:
- Extremely narrow laser linewidths (long coherence lengths) are required in precision spectroscopy, quantum optics and metrology. The linewidth of atomic transitions between long-lived energy states may be as narrow as a few Hertz. On the laser side, this calls for additional high-bandwidth frequency stabilization, attainable with TOPTICA’s locking modules such as FALC and DigiLock.
- By contrast, applications like molecular spectroscopy or optical pumping of Doppler-broadened gases are faced with absorption signatures several 100 MHz wide. Here, one prefers an artificially broadened laser linewidth, which has been difficult to achieve with semiconductor lasers. Now, controlled and reproducible broadening has become possible with TOPTICA’s Laser Coherence Control unit LCC.
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The attainable coherence spectrum of TOPTICA’s diode lasers covers more than 12 orders of magnitude – from spectrally broad violet diodes to new records in frequency resolution. |
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