Dichroic filters are thin filters that only allow a certain band of wavelengths to pass through while reflecting all other wavelengths. Long pass, short pass, band pass, band reject, IR-cut, and color correction varieties of high-quality dichroic filters are available for a variety of wavelengths from Alfa Chemistry. These made-to-order goods are expertly produced to adhere to precise specifications. Because color is essentially part of the filter, it does not fade, giving our filters a longer life than other conventional filters. Our dichroic filters also provide outstanding transmission, reflection, and absorption properties and have a very high threshold for laser damage. To learn more about your demands for a custom bandpass filter, please contact our technical sales team.
Customized Service
Alfa Chemistry customizes a range of dichroic filters, including 45° reflective dichroic filters that reflect one color while transmitting all other visible wavelengths, dichroic short-pass and dichroic long-pass filters designed for visible or near-infrared light, and fluorescent dichroic filters with cutoff wavelengths at common fluorophore emission wavelengths. Custom dichroic filters with performance to fit customers' needs and budgets are available. For all dichroic filter types, the following specifications are the most frequently asked for.
| Available Size | Square 7 mm~300 mm, Diameter 10 mm~400 mm |
| Cutting Tolerance | +/-0.2 mm |
| Glass Substrate | Soda-Lime glass, Tempered glass, Borosilicate glass, Borofloat glass, etc |
| Dichroic Filter Types | Longpass, shortpass, bandpass, bandblocking, hot and cold mirrors, IR and UV cut-off |
| Wavelengths | 300~1200 nm dependant on type |
| Wavelength Accuracy | +/-5 nm |
| Transmission | TMax=95% typical dependant on type and substrate |
They are available in a wide range of sizes with suitable thin film dielectric coatings that transmit wavelengths in the specified transmission band and reflect all other wavelengths. To ensure that all components satisfy our high requirements for quality, our highly trained specialists use a spectrophotometer to examine each component individually.
Types of Dichroic Filters
All wavelengths above a specified cutoff wavelength are transmitted by long-pass filters. Conversely, short-pass filters let through wavelengths that are below a specified cutoff wavelength. In order to eliminate extra heat from the system, dichroic short-pass and long-pass filters can also function as hot and cold mirrors, respectively.
The cold mirror, when positioned behind a light source, reflects all visible light forward and emits undesired NIR light at a 45° angle. The heated mirror will transmit visible light at a 0° angle while reflecting NIR heat.
Fig 1. (A) Epifluorescence, (B) confocal microscopy, and (C and D) TIRF microscopy. The excitation beams are in green and the emitted fluorescence is shown in red. The preparation is separated from the objective lens by a glass coverslip and immersion oil. (Bretschneider F, et al. 2019)
In our cutting-edge metrology laboratory, our qualified personnel test each product to make sure it complies with requirements. If you need technical advice, please contact our technical team to learn more about our high-quality services.
Reference
- Bretschneider F, et al. (2019). "Microscopy and Optical Methods in Electrophysiology." Introduction to Electrophysiological Methods and Instrumentation (Second Edition). 10: 285-310.