Ultrafast Laser Mirrors for Femtosecond Systems
Did You Know?
Did you know that a mirror designed for 99.8% and tightly specified GDD (e.g., −50 to +20 fs²) to avoid pulse stretching and satellite pulses in CPA or oscillator cavities. A common misconception is that any high-reflectivity dielectric mirror is suitable for femtosecond operation—yet even small uncontrolled GDD ripple on the order of tens of fs² can significantly distort sub-50 fs pulses over multiple bounces.
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Frequently Asked Questions
Ultrafast laser mirrors are dielectric-coated mirrors engineered for high reflectivity and controlled dispersion at the bandwidths and peak powers of femtosecond and picosecond lasers. Unlike standard dielectric mirrors optimized for narrowband CW or nanosecond sources, ultrafast mirrors are designed to manage group delay (GD) and group delay dispersion (GDD) over a broad spectral range while withstanding high peak intensities without nonlinear distortions.
Ultrafast mirrors introduce wavelength‑dependent phase shifts, characterized by group delay (first derivative of phase vs. angular frequency) and group delay dispersion GDD (second derivative). Non‑optimized GDD stretches or distorts femtosecond pulses, so mirrors are often designed with low, flat GDD (near‑zero) for pulse preservation or with tailored negative/positive GDD to compress or pre‑compensate pulses in CPA and oscillator setups.
Common variants include broadband high‑reflector (HR) mirrors, chirped mirrors (CMs), double‑chirped mirrors (DCMs), and hybrid metal‑dielectric mirrors. Broadband HRs aim for high R with modest dispersion control, chirped and double‑chirped mirrors provide engineered GDD over tens to hundreds of nanometers for pulse compression, while metal‑dielectric designs trade slightly lower reflectivity for wider spectral coverage and reduced sensitivity to angle and polarization.
Critical parameters include central wavelength and bandwidth, reflectivity (often >99% over the specified range), GDD profile (value and flatness), and damage threshold for both average and peak power. You should also consider angle of incidence (AOI), polarization (s‑, p‑, or random), substrate material and thickness (thermal and mechanical stability), and surface quality/flatness required by your beam size and wavefront tolerances.
Compare published R(λ) and GDD(λ) curves over your full spectral bandwidth at the intended AOI and polarization, rather than relying only on single numbers at the center wavelength. For oscillators, prioritize low and smooth GDD to avoid pulse shaping; for CPA compressors or stretcher/compressor pairs, match the integrated dispersion budget of the entire beam path, including fibers, crystals, windows, and any additional optics.
Standard catalog ultrafast mirrors for common wavelengths (e.g., 800 nm Ti:sapphire, 1030/1064 nm Yb/Nd) often ship in 1–3 weeks, while custom designs with specific GDD profiles, AOIs, or apertures can take 4–8 weeks depending on coating complexity and batch scheduling. Pricing is mainly driven by coating design complexity (e.g., double‑chirped, ultra‑broadband), substrate size and material, surface quality/flatness specs, and volume; small custom runs with tight tolerances are significantly more expensive per piece than off‑the‑shelf parts.
On FindLight, navigate to Optics → Mirrors → Ultrafast Laser Mirrors, then filter by wavelength range, reflectivity, substrate, AOI, and form factor to narrow down suitable options. You can open multiple product pages to compare specs and datasheets side by side, then use the built‑in “Request Quote” or contact form on each listing to send technical requirements directly to suppliers without registration; responses are handled by email or the supplier’s own CRM.
Overview of Ultrafast Laser Mirrors
Ultrafast Laser Mirrors are precision dielectric mirrors engineered for femtosecond and picosecond laser systems, where dispersion and damage threshold are critical. These mirrors are typically based on multilayer dielectric stacks on low-loss substrates, optimized for a narrow wavelength band with controlled group delay dispersion (GDD) and high reflectance.
Key Specifications and Parameters
When evaluating Ultrafast Laser Mirrors, buyers should focus on several technical parameters that determine performance in ultrashort pulse applications:
- Central wavelength and bandwidth: Common designs target Ti:sapphire (700–1100 nm), Yb-based lasers (~1020–1080 nm), Nd:YAG (1064 nm), or telecom bands (around 1550 nm). Verify that the mirror’s high-reflectance band covers the full laser spectrum and any spectral broadening.
- Reflectance (R): Ultrafast Laser Mirrors often provide R > 99.5% for s- and p-polarization at a specified angle of incidence, typically 0°, 5°, or 45°. Check polarization dependence if using non-normal incidence.
- Group Delay Dispersion (GDD): Low or tailored GDD (e.g., < ±20 fs² over the working bandwidth) is essential to preserve pulse duration. Chirped or dispersion-compensating mirrors may provide negative GDD for pulse compression.
- Damage threshold: Specified in J/cm² for femtosecond pulses and W/cm² for average power. Ultrafast Laser Mirrors must handle high peak intensities without coating degradation.
- Substrate and surface quality: Fused silica and ultra-low expansion glasses are common. Surface quality might be specified as 10-5 or 20-10 scratch-dig with λ/10 or better flatness, depending on application.
- Mounting geometry: Diameter, thickness, and edge treatment should match your optomechanical holders to maintain beam pointing stability.
Typical Applications
Ultrafast Laser Mirrors are used in oscillator and amplifier cavities, pulse compressors, stretcher/compressor stages, pump-probe setups, nonlinear optics experiments, and beam steering in femtosecond micromachining or multiphoton microscopy systems.
Buyer Guidance on FindLight
On FindLight, you can compare Ultrafast Laser Mirrors by wavelength range, reflectance, GDD, angle of incidence, substrate, and clear aperture. Review detailed datasheets to ensure compatibility with your laser source and pulse duration, then request quotes directly from suppliers. Ultrafast Laser Mirrors can be sourced without registration, enabling rapid specification checks and procurement for R&D labs and OEM integration alike.