Shortpass filters are commonly used to isolate regions of a broad spectrum. The role of this type of filter is to transmit energy over a specified band at wavelengths shorter than the cut-off wavelength, and to block the transmittance of energy at wavelengths longer than the cut-off wavelength. In addition, shortpass filters are useful for custom bandpass filtering by using with longpass filters. Asahi Spectra offers a wide variety of shortpass filters in the broad wavelength range: ultraviolet, visible, or infrared wavelengths.

Longpass filters are commonly used to isolate regions of a broad spectrum. The role of this type of filter is to transmit energy over a specified band at wavelengths longer than the cut-on wavelength, and to block the transmittance of energy at wavelengths shorter than the cut-on wavelength. In addition, longpass filters are useful for custom bandpass filtering by using with shortpass filters. Asahi Spectra offers a wide variety of longpass filters in the broad wavelength range: ultraviolet, visible, or infrared wavelengths.

Bandpass filters are commonly used to transmit a well-defined wavelength band of the spectrum while rejecting both the long and short wavelength sides of the transmission band. Our coating designs are based on multiple cavity resonators. Thus, our bandpass filters have very steep slopes and very high attenuation outside of the narrow pass 10nm band. Asahi Spectra offers a wide variety of bandpass filters in the broad wavelength range: ultraviolet, visible, or infrared wavelengths.

Our UV filters are manufactured by hard coating, such as ion assisted deposition (IAD) and magnetron sputtering (MS). These coating methods achieve hard coating, excellent durability for environment (humidity, low or high temperature, thermal shock or vacuum) and stability of spectral performance.

Neutral density filters are the reflective type of ND filters, which are used to control the light intensity. Coated chromel layer attenuates the light by mainly reflecting and partially absorbing. Our ND filters are designed to keep spectrally even performance especially in VIS range without altering the relative spectral distribution of the energy. Still they are available from UV through IR because the substrate material is fused silica. 6 kinds of attenuation rate are available.

Super cold filters are heat-reflective type which have much better performance than a conventional heat-absorptive type. Even with a high power light source, the substrate will not be damaged because it is reflective type and made of fused silica. VIS transmitting type (750nm cutoff) and VIS-NIR transmitting type (1050nm cutoff) are available.

We have provided astronomical filters, dichroic beam splitters, or windows with broadband AR to world's well-known observatories in Chile, Hawaii, Canary, and Arizona for over twenty years. Unlike cheap astronomical filters for amateurs sold online, Asahi astronomical filters are fabricated to meet many hard requirements for sciences from professional astronomers.
We are always willing to challenge new technologies to cooperate with the unique instruments.

We launch to produce optical and NIR filters for the purpose of defense, security or sensing by using magnetron sputtering. The interference film coated by sputtering has excellent durability against the cryogenic, heat or humidity. Spectral performance is quite stable and reliable in a tough environment. Large size is available as well.

Optics used for photolithography requires the environmental durability against high temperature and high efficiency in transmission and reflection to contribute a production yield. We provide bandpass filters for mercury emission lines, longpass filters, or cold mirrors coated by ion assisted deposition (IAD) method.