Filters picture
Home / Product Selection / Thin Film Coatings / Hot Mirrors, SIR Series

Hot Mirrors

Dielectric heat reflective coatings

Special Properties

  • Colour-neutral and efficient separation of light and heat energy
  • High and neutral optical transmission
  • Excellent infrared reflection up to 1100 nm
  • Dielectric coating design
  • High operating temperature range up to 400 °C
  • High quality borosilicate glass substrate
  • Works the opposite way of dichroic cold mirrors

Typical Applications

  • Heat reflecting optics in lighting systems
  • Optical mirrors for infrared laser diodes
  • Infrared filters for light sources
  • IR-cut filter optics for CCD camera chips
  • Sensor- and measurement applications
  • Automotive lighting
  • Detector trimmer optics
  • Mirrors for eye-tracking systems
  • Laser injector optics
  • Projector filter

Related filters and coatings

Request for Quotation

48h-Express Service for customized optics, logo Also available in 48 h Express-Service

Hot mirrors are dichroic heat-reflecting optics that filter out thermal energy from a light beam by reflecting infrared light and simultaneously transmit the visible wavelength spectrum. Hot mirror optics are based on the opposite optical function principle of a cold mirrors. Since they reflect infrared light and because they filter the infrared wavelengths out of the beam path, they can be referred to as heat-reflection filters as well as to heat reflection mirrors. Both terms are correct and common.

CNC-shaped SIRThe SIR hot mirror offers a decisive advantage over standard IR-reflection hot mirror coatings and heat absorbing filters. Its optical transmission of visible light is higher and more color neutral, while it reflects the thermal radiation in the near infrared up to 1100 nm significantly more efficiently.

Because of the all dielectric optical design and the thermally resistant quality BOROFLOAT® glass substrates we use for the SIR-hot mirrors, they can withstand a high temperature-load. The filters can operate at temperatures up to 400 °C which enables the use in high energy lighting systems. The SIR hot mirror does not get as hot as absorbing filter optics, because the warm infrared radiation is reflected back to the light source instead of being absorbed by the optics.

However, there are also purely optical applications for our SIR mirror. For example, the SIR hot mirrors are often used as so called detector trimmer optics in front of a digital camera chip to prevent the optical image sensor from saturation caused by the near-infrared light, for which many CCD camera sensors are very sensitive.

The non-metallic coating construction makes the SIR hot mirror resistant to heat and humidity. The optical coating is optimized for maximum possible transmittance of visible light and maximum reflectivity in the NIR-range at the same time. The angle of incidence the SIR-hot mirrors are designed for is 0°. However, if a slight shifting of the cut-off wavelength is acceptable, our standard SIR mirror can also be used at 45°. At this angle of incidence, most of the visible spectrum is still transmitted, and the reflected IR-image keeps a good optical imaging quality. Hence, the SIR mirrors are often found as optics in eye-tracking applications or in IR-laser injection systems without modifications required. The use of our standard hot mirror can reduce the cost in such cases drastically compared to a customized optical coating, especially if only small quantities are needed. If you want to utilize our SIR mirror at incidence angles that differ from 0°, please send us an inquiry by email or open our support form to ask for further information. Typical optical transmission curves of our hot-mirrors, when operated at 45° or other angles of incidences, can be obtained on request.

Please note that we can modify all of our hot mirror coatings regarding transmittance and reflection wavelength ranges. Same applies to the optical cut-on and cut-off filter-wavelength and for the angle of incidence. Please use our custom optics inquiry form to request a quote for your individually designed hot-mirrors conveniently. You are welcome to contact us by email for help, further information, and more details.


To receive a quotation for our SIR-hot mirrors with individual dimensions, please click the button below:


Request for Quotation



SIR, optical transmission curve

View optical transmission curve of our SIR hot mirrors

Product Code

  • SIR hot mirror



  • All-dielectric, multilayer mirror/filter coating
  • Designed for an angle of incidence of 0°
  • Customized cut-on and cut-off wavelength per request

Operating Temperature

  • up to 400 °C

Optical Flatness

Surface Quality

  • typ. 80-50 scratch & dig (MIL-0-13830A)
  • Other on request

Standard Thicknesses

Other Properties

  • Adherence according to MIL-C-675 C (tape test)
  • Abrasion-resistant according to MIL-M-13508 C

Note: If you are looking for optical mirrors with reverse functional characteristics, please take a look at our cold mirror web site. In case you search for infrared mirror optics, please visit the data-sheet of our SEA-NIR, SEA-UV optics and the spec-sheet of our ITO-coatings, which, at higher film thickness, can reflect the infrared range.


All given details and specifications are mean reference values and are not guaranteed. Also, please consider our "Notes on technical specifications".

© 1994 - 2019 Präzisions Glas & Optik GmbH