Cut-off optical glass is an optical material capable of selectively transmitting or blocking light within specific wavelength ranges. It is widely used in optical imaging, spectral analysis, photography equipment, and industrial inspection. Its core function is to achieve a sharp spectral division at a specific wavelength (referred to as the "cut-off wavelength"), creating high-transmission and high-blocking regions to precisely control light propagation.
1. Basic Classification and Working Principles
Stop-type optical glass is primarily divided into two categories:
Long-pass filter (short-wave cutoff type): Allows long-wavelength light to pass while blocking short-wavelength light, such as red or infrared glass.
Short-wave pass filter (long-wave cutoff type): Allows short-wavelength light to pass while blocking long-wavelength light, such as ultraviolet or blue glass.
Based on the mechanism of action, it can be categorized as:
Absorption type: Relies on metal ion doping (e.g., copper, cadmium sulfide) in the glass body to absorb specific wavelength light, such as Schott BG47 blue glass enhancing infrared absorption capacity through copper ions.
Thin-film interference type: Multiple dielectric films are deposited on the substrate to achieve spectral selectivity through optical interference effects, commonly used in high-precision optical systems.
Combined Type: Integrates absorption and interference technologies to enhance cutoff steepness and blocking depth, suitable for complex optical environments.