Dichroic Beamsplitters

Dichroic beamsplitters are optical filters designed to selectively transmit and reflect incident light based on wavelength. Avantier’s dichroic beamsplitters offer high transmission for specific wavelengths while reflecting others, enabled by precision-engineered coatings. With a steep cut-off point between transmission and reflection bands, these beamsplitters allow efficient wavelength-based beam separation. For enhanced performance, our beamsplitters are often equipped with anti reflective coatings, which minimize unwanted reflections and ensure optimal light transmission within the designated wavelength range.

Types of Dichroic Beam splitters and Their Applications

Longpass dichroic beamsplitters

Longpass dichroic beamsplitters reflect shorter wavelengths and transmit longer ones. They are often used in fluorescence microscopy to reflect excitation light toward a sample while allowing emitted light to pass through the filter. They are also useful for beam combining in laser launches or for Raman (Stokes) applications, reflecting laser light toward a sample while transmitting the Raman signal.

Shortpass dichroic beamsplitters

Shortpass dichroic beamsplitters transmit shorter wavelengths while reflecting longer ones. Shortpass filters are ideal for multiphoton laser scanning, where emission has a much shorter wavelength than the excitation laser, or for second-harmonic imaging, where light is emitted at half the laser wavelength.

Multiband dichroic beamsplitters

Unlike longpass or shortpass filters, which have a single reflection band and a single transmission band, multiband dichroic beamsplitters contain alternating reflection and transmission regions. These are used for applications like rapid laser or LED switching.

Specifications of Longpass and Shortpass Dichroic Filters

Key specifications of longpass and shortpass dichroic filters include:

Wavelength range of the transmission band, along with its average percentage transmission for that band
Wavelength range of the reflection band, and the average reflection transmission for that band. This is often described in terms of blocking.
Angle of incidence of the beamsplitter (45 degrees is the usual, but other angle of incidences are possible)
Cut on and cut off wavelengths (calculated as the wavelength at 50% of peak transmission)
Edge steepness, describing the sharpness of the transition from transmission to reflection

Custom Dichroic Beamsplitters

At Avantier, we are fully equipped to produce custom dichroic beamsplitters tailored to your exact specifications. Whether you need a shortpass filter for second-harmonic imaging or a longpass filter for fluorescent microscopy, we deliver. Our beamsplitters are designed with narrow spectral band edge tolerances to ensure maximum spectral stability, low residual optical absorption losses, and excellent environmental stability.

At Avantier, we don’t rely on in-stock products that might almost meet your needs. Instead, we work with you to determine exactly what you require and then create a fully custom optic. That’s the Avantier difference—high-quality, customized optics that meet your precise specifications. Don’t settle for something that almost works—choose custom-made optics. Please contact us today to place an order or schedule a consultation with our experienced optical designers.