800nm Chirped Mirror HD1401-25.4-6.35

Overview

The 800nm Chirped Mirror -450fs² (HD1401-25.4-6.35) delivers mid-range negative group delay dispersion (GDD) of -450 fs² per bounce, optimized for 775 nm center wavelength operation across the 725–825 nm spectral range. This 775nm chirped mirror provides efficient GDD compensation for Ti:Sapphire laser systems requiring moderate dispersion control without the space constraints of lower-GDD designs. With 13 bounces compensating approximately 6000 fs² of accumulated positive dispersion, this mirror enables compact external compressor architectures and intracavity dispersion management in chirped pulse amplification (CPA) systems.

The -450 fs² GDD value occupies a critical design space between low-dispersion oscillator mirrors and high-dispersion bulk compressors, offering superior phase control for systems where material dispersion from gain media, optics, and beam transport accumulates to several thousand femtoseconds squared. This specification reduces optical path complexity compared to -100 fs² mirrors while maintaining precise group velocity dispersion (GVD) correction across the full Ti:Sapphire bandwidth.

Applications

• Ti:Sapphire CPA systems: External pulse compressor stages for regenerative and multipass amplifiers generating sub-100 fs pulses
• OPA and OPCPA pump line conditioning: Pre-compensation of dispersion in 800 nm pump beams before nonlinear frequency conversion
• Kerr-lens mode-locked oscillators: Intracavity dispersion management for extended-cavity Ti:Sapphire lasers requiring negative GDD beyond standard HR coatings
• Stretcher-compressor pairs: Compact compressor designs in femtosecond laser systems with moderate CPA ratios

Construction & Performance

Manufactured by Ultrafast Innovations on 25.4 mm diameter, 6.35 mm thick UVFS substrates with ion beam sputtered (IBS) multilayer coatings. Specified for P-polarization at 5° angle of incidence (AOI) with R>99% reflectance across the entire 725–825 nm range. The chirped dielectric stack provides broadband GDD compensation while maintaining >99% reflectivity, minimizing throughput losses in multi-bounce compressor configurations. LIDT rated at 0.2 J/cm² for femtosecond pulse durations.

Storage & Handling

Operate at 25 °C, 40–60% RH. Clean only with >99% optical-grade ethanol and lint-free lens tissue using single-pass drag method. Avoid abrasive cloths and water.