The 365nm narrowband filter is a precision optical component for the ultraviolet band, specifically designed to filter 365nm wavelength light. It achieves precise control of specific spectra through high-precision coating technology. Its core advantages include an ultra-narrow bandwidth (as low as 0.1nm) and high transmittance (over 90%), along with excellent out-of-band blocking capability (e.g., OD6 level), effectively suppressing visible light and other interfering bands to ensure high-purity transmission of the target spectrum.

Key Performance Parameters

• Center Wavelength (CWL): 365nm, with tolerance controllable within ±0.05nm, meeting the requirements of high-precision optical systems.
• Full Width at Half Maximum (FWHM): As narrow as 0.1nm, with a "flat-top" passband shape and fast roll-off edges, forming an approximately square spectral curve, suitable for applications with stringent wavelength selectivity.
• Transmittance: Over 90% at the 365nm center wavelength, with uniform transmission within the passband, ensuring stable signal intensity.
• Out-of-Band Blocking: Up to OD6 level (i.e., 99.9999% blocking rate), effectively filtering non-target band light and reducing background noise.

Technical Principle and Manufacturing Process

The 365nm narrowband filter is based on the thin-film interference principle. Through precision coating processes such as SIRRUS plasma deposition, multiple layers of high and low refractive index dielectric films are alternately deposited on optical substrates (e.g., quartz or glass). By controlling the thickness and number of layers, these films enable constructive interference for 365nm wavelength light to transmit, while other wavelengths are blocked due to destructive interference. The manufacturing process must meet the following requirements:

• Substrate Selection: Quartz substrates are commonly used in the ultraviolet band to reduce UV light absorption.
• Coating Precision: The thickness error of each film layer must be controlled at the nanoscale to ensure spectral consistency.
• Hard Coating Treatment: Hard coating technology is employed to enhance the film's wear resistance and laser damage resistance, extending its service life.

Typical Application Fields

1. Scientific Research and Analytical Instruments

• Fluorescence Microscopy: Serves as an excitation filter to precisely excite 365nm ultraviolet fluorescent probes, improving imaging contrast.
• Raman Spectroscopy: Used in laser excitation light paths to filter stray light for high signal-to-noise ratio molecular vibration spectra.
• DNA Sequencing: Functions as a laser line filter in genetic analysis to ensure the accuracy of sequencing signals.