1. What is a PicoPulse™ or CVBG grating?

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PicoPulse™ filters are solid‑glass volume holographic gratings (CVBG) for with gradually varying index modulation period designed specifically for laser pulse stretching and compression, offering compact, robust, high‑efficiency alternatives to ruled gratings and fiber Bragg gratings (FBGs).

 

2. What are typical applications?

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• Chirped Pulse Amplification (CPA) systems requiring pulse stretching and recompression. 

• Systems where compact, alignment‑friendly chromatic dispersion elements are needed. 

 

3. How does a CVBG work?

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A CVBG has a linearly varying grating period along the propagation axis:

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• Shorter and longer wavelengths are diffracted at different depths, creating a linearly varying group delay that stretches or compresses the pulse depending on direction.

   

4. What advantages do PicoPulse™ and CVBGs offer versus ruled gratings?

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• Compact geometry with drastically reduced footprint and simpler alignment. 

• High laser‑induced damage threshold for high‑energy / high‑power systems.

• Low scatter, high efficiency, and near‑diffraction‑limited output beam quality after stretching/compression.

• Environmental stability, including temperature tolerance and mechanical robustness. 

   

5. What key performance specifications are available?

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PicoPulse™ (Coherent/Ondax)

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• Center wavelength range: 1029–1300 nm (custom wavelengths: 400–2000+ nm available).

• Dispersion rate: 10–100 ps/nm (50 ps/nm standard). 

• Spectral bandwidth: 1–10 nm typical. 

• Stretched pulse length: 200–300 ps. 

• Diffraction efficiency: ~90% in free space. 

 

6. What power handling capabilities do these gratings have?

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• PicoPulse™ supports many orders of magnitude higher power than fiber Bragg gratings or gel‑based gratings suitable for industrial applications.    

 

7. What beam quality can be expected?

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• PicoPulse™ maintains distortion‑free, round, near‑diffraction‑limited output after stretching and compression, even over varying temperatures (13°C–60°C). 

 

8. Can these gratings function as both stretchers and compressors?

 

Yes.    CVBGs inherently support bidirectional use, acting as stretchers or compressors depending on which facet the laser enters. 

 

9. Are custom versions available?

 

Yes.   Please contact.    

 

10. What are typical mounting and mechanical details?

 

Size depends on application and specifications.​

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11. What is the difference between vacuum and air-referenced wavelengths?

 

Because we tightly control wavelength accuracy and tolerance, it is important to specify the reference medium used for wavelength measurement.

 

Light travels slightly more slowly in air than in vacuum, causing the wavelength in air to be marginally shorter. To avoid ambiguity and ensure consistency, wavelengths in our datasheets are vacuum‑referenced, which is also the convention used by many spectroscopy databases.  As an example, a HeNe laser specified at 632.991 nm in vacuum corresponds to 632.816 nm in air. This difference does not indicate a physical change in the laser, only a difference in how the wavelength is referenced.