Linear Variable Filters

We've combined our patented high-pass and low-pass Linear Variable Filters to create the world's first notch filter with an adjustable center wavelength and adjustable bandpass. Each filter features an excellent transmission band (~90%) and blocking band (99.8%).

These filters -- with interference coatings applied to 57 mm x 10 mm quartz substrates -- are especially useful for spectrally shaping the excitation energy from broadband sources used for fluorescence.

Features

Slide Carriers

These off-the-shelf filters are epoxied into slide carriers that allow you to move the transmission or blocking band throughout the 300-750 nm wavelength range.

Single High-pass and Single Low-pass Filter

The LVF-H High-pass Filter is a single filter that blocks light at 98.8% until a transition wavelength that varies along its length. At that point, the LVF-H passes light better than 90%. The LVF-L Low-pass Filter is a single filter that passes light at 88% until a transition wavelength that varies along its length. At that point, the LVF-L blocks light better than 98.8%.

Double High-pass and Double Low-pass Filters

We take two identical LVF-H or LVF-L filters, align them so that the transition wavelengths of both filters are matched and then epoxy them together in their slide carriers. The benefit of having double filters versus a single filter is that the optical density of the blocking band increases to 99.96%. However, the transmission band is reduced to 80%.

High-pass and Low-pass Variable Bandpass Filters

By fastening together a high-pass filter and a low-pass filter, we created a variable bandpass notch filter that allows you to adjust the center wavelength and the bandwidth. We preset the transmission bandwidth at ~25 nm FWHM, but adjusting four screws allows you to slide the filters against one another to create a wider or narrower transmission bandwidth (~20 nm bandwidth minimum).

LVF-HL (300-750 nm) and LVF-UV-HL (230-500 nm) LVFs are changing the way that scientists approach traditional fluorescence spectroscopy measurements by eliminating the need for multiple, expensive bandpass filters and by spectrally shaping the excitation energy from a single broadband source. A single LVF cassette ($577) can replace multiple filters that often cost more than $100 each. Additionally, LVF sets enable the user to shape the excitation energy from a single broadband source as opposed to using multiple light sources with various wavelengths or a front-end scanning monochromator.

LVF Options

LVF Accessories

The LVF filters and slide carriers can be inserted into spectrometer setups using these accessories (see prices at bottom of page):

LVF-H High-pass Filter Spectra

The transition wavelength from blocking to transmission band varies according to the filter's position in front of the collimating lens.

LVF-L Low-pass Filter Spectra