Vintage Photo Technical Research (PTR) SF400 Ultra Precision Blazed Reflection Diffraction Grating

Rare vintage high-precision blazed reflection diffraction grating from Photo Technical Research, Inc. (PTR), a pioneering 1960s–1970s optics company known for early holographic and laser-related components. This SF400 model is an ultra-high-density grating optimized for mid-infrared applications, yet still highly effective in visible light for striking rainbow diffraction effects.

Key Specifications:

• Groove Density: 3600 grooves/mm (extremely fine spacing for superior resolution)

• Blaze Wavelength: 5 microns (5000 nm) – peaked efficiency in the mid-IR range

• Type: Blazed reflection (likely holographic mastering for low stray light)

• Substrate: Solid aluminum (excellent thermal stability, soft reflective surface)

• Dimensions: 1″ (25.4 mm) diameter x 10 mm thick – robust, mountable blank ideal for stable setups

• Coating: Unprotected aluminum

This thick aluminum substrate provides exceptional mechanical and thermal stability, making it suitable for spectroscopy, laser beam combining, high-resolution monochromators, IR research, or educational/hobbyist demonstrations. The high groove density delivers outstanding dispersion, while the 5μm blaze ensures strong first-order efficiency in the 4–6μm region.

Stored in its original Photo Technical Research jar (labeled “Ultra Precision Grating,” catalog SF400) – a nice historical touch for collectors of vintage optics. PTR pieces from this era are increasingly scarce, as the company is long defunct.

Perfect for labs, researchers, universities, or optics enthusiasts seeking a genuine piece of holography/laser history that still performs beautifully. Sold as-is, but visually and functionally excellent.