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LLTF CONTRAST™

Laser Line Tunable Filter

The Laser Line Tunable Filter (LLTF CONTRAST) is a non-dispersive patented (US patent 7557990) tunable bandpass filter based on volume Bragg gratings. It combines very high optical density (> OD6), an outstanding out-of-band rejection, and wide tunability. The LLTF can be customized to cover the entire 400 nm to 2500 nm spectral range with a high spectral resolution.

It can be coupled with a wide variety of broadband sources to create a tunable laser source. It can also be used as a cleanup filter for spectroscopy applications.

There are numerous possible LLTF configurations whose spectral range and bandwidth can be finely tuned to fit specific needs. The specifications below of several tried-and-tested standard models may serve as a starting point.

Product Specifications

Technical Specifications - Standard Resolution
CONTRAST-SR-VIS CONTRAST-SR-SWIR CONTRAST-EXT III CONTRAST-EXT IV
Spectral range 400-1000 nm 1000-2300 nm (2500 nm optional) 400-1700 nm 400-2300 nm (2500 nm optional)
Bandwidth (FWHM) 1.5 - 2.5 nm 2.0 - 5.0 nm 400-1000 nm: 1.5 - 2.5 nm | 1000-1700 nm: 2.0 - 5.0 nm 400-1000 nm: 1.5 - 2.5 nm | 1000-2300 nm: 2.0 - 5.0 nm
Out-of-band rejection <-60 dB@±40 nm, typically <-30 dB@±10 nm <-60 dB@±80nm, typically <-30 dB@±20nm 400-1000 nm: <-60 dB@±40 nm, typically <-30dB@±10 nm | 1000-1700 nm: <-60dB@±80 nm, typically <-30 dB@±20 nm 400-1000 nm: <-60 dB@±40 nm, typically <-30dB@±10 nm | 1000-2300 nm: <-60dB@±80 nm, typically <-30 dB@±20 nm
Peak efficiency Typically around 65% Typically around 65% Typically around 65% Typically around 65%
Optical density (OD) > OD6 (measured at 1064 nm) > OD6 (measured at 1064 nm) > OD6 (measured at 1064 nm) > OD6 (measured at 1064 nm)
Stabilization time/wavelength step 20 ms < 1 nm; 25 ms / 1 nm; 28 ms / 2 nm; 35 ms / 5 nm; 50 ms / 10 nm 20 ms < 1 nm; 25 ms / 1 nm; 28 ms / 2 nm; 35 ms / 5 nm; 50 ms / 10 nm 20 ms < 1 nm; 25 ms / 1 nm; 28 ms / 2 nm; 35 ms / 5 nm; 50 ms / 10 nm 20 ms < 1 nm; 25 ms / 1 nm; 28 ms / 2 nm; 35 ms / 5 nm; 50 ms / 10 nm
Dimensions (L x W x H) 9 x 6.3 x 6.7 (inches), 23 x 16 x 17 (cm) 9 x 6.3 x 6.7 (inches), 23 x 16 x 17 (cm) 9 x 6.3 x 6.7 (inches), 23 x 16 x 17 (cm) 11.8 x 9.1 x 6.7 (inches), 30 x 23 x 17.4 (cm)
Options & Accessories
Fibered output An X-Y-Z translation adjustment allows coupling optimization. FC\APC standard connector (SMA, FC\PC on demand). Both lens and mirror-based models available An X-Y-Z translation adjustment allows coupling optimization. FC\APC standard connector (SMA, FC\PC on demand). Both lens and mirror-based models available An X-Y-Z translation adjustment allows coupling optimization. FC\APC standard connector (SMA, FC\PC on demand). Both lens and mirror-based models available An X-Y-Z translation adjustment allows coupling optimization. FC\APC standard connector (SMA, FC\PC on demand). Both lens and mirror-based models available
Harmonic filter Second harmonic suppression included over the 400-500 nm spectral range Second harmonic suppression included over the 850-1250 nm spectral range. Additional filter for 500-850 nm harmonic suppression available upon request Second harmonic suppression included over the 400-850 nm spectral range Second harmonic suppression included over the 400-850 nm spectral range
Alignement kit In free space configuration (input/output), the alignment kit allows the user to rapidly find the correct alignment. In free space configuration (input/output), the alignment kit allows the user to rapidly find the correct alignment. In free space configuration (input/output), the alignment kit allows the user to rapidly find the correct alignment. In free space configuration (input/output), the alignment kit allows the user to rapidly find the correct alignment.
Technical Specifications - Higher Resolution
CONTRAST-X
Spectral range X represents a custom spectral range: up to 5 gratings.
Bandwidth (FWHM) 0.15 - 0.9 nm
Out-of-band rejection Typically -55 dB @± -5 nm
Peak efficiency Typically around 65%
Optical density (OD) Depends on spectral range
Stabilization time / wavelength step 20 ms < 1 nm; 25 ms / 1 nm; 28 ms / 2 nm; 35 ms / 5 nm; 50 ms / 10 nm
Dimensions (L x W x H) 9 x 6.3 x 6.7 (inches), 23 x 16 x 17 (cm)
Options & Accessories
Fibered output An X-Y-Z translation adjustment allows coupling optimization. FC\APC standard connector (SMA, FC\PC on demand). Both lens and mirror based-models available
Harmonic filter Upon request
Alignement kit In free space configuration (input/output), the alignment kit allows the user to rapidly find the correct alignment.

Spec Sheet

Publications

Videos

Introduction to the Laser Line Tunable Filter - LLTF

The LLTF combines a wide spectral tunability (400-2300 nm) with the highest out-of-band rejection (< -60 dB) available on the market. When coupled to a supercontinuum source, the LLTF is an ideal tool for spectroscopy, calibration and hyperspectral imaging.

OptinaDx Retinal Deep Phenotyping platform™

White Papers

Overview of Laser Line Tunable Filters and Tunable Laser Sources Applications

Authors Laura-Isabelle Dion-Bertrand

Abstract

The Laser Line Tunable Filter (LLTF) is a non-dispersive, widely tunable bandpass optical filter. At its core lies a volume Bragg grating (VBG) which efficiently selects and filters all but a narrow spectral window from a broadband light source. The LLTF provides a wider tunable range than other commercially available tunable filters. A single filter has the potential to offer full continuous…

Download the white paper

Widely Tunable Filter: Technology & Measurement of Critical Specifications

Authors Daniel Gagnon and Laura-Isabelle Dion-Bertrand

Abstract

The out-of-band rejection and the optical density (OD) are two critical specifications of tunable filters. Unfortunately, these properties are often misinterpreted and their definitions tend to differ from one manufacturer to another. End users need to be careful when looking over the specifications of a filter. Also, the measurement of these properties for customers can be laborious. One needs…

Download the white paper

Custom Products

Beyond our standard product lines, we bring to bear our know-how through collaborations with industry and researchers both local and international. It’s in our DNA to build systems that measure up to the high standards set by our customers in science and industry. Please contact us if you don’t see what you are looking for in our standard product lines.

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