Wavelength Control

Center wavelength is controlled manually via the front panel of the LCTF controller and allows programmable switching sequences. The controller offers three BNC connectors (Trigger In, Trigger Out, and Analog In) allowing the LCTF to be synchronized with a number of different devices such as scientific cameras or motion control stages. Each Kurios LCTF is factory calibrated and includes a switching time map to allow the user to optimize the system to their specific system requirements.

The Trigger In connector allows Kurios to be controlled by another device via a TTL signal. It can be used, for instance, to synchronize Kurios with a scientific camera, such that every time the camera captures an image, the filter is immediately advanced to the next wavelength in the sequence. Kurios triggers on the falling edge of the 5 V TTL signal.

The Trigger Out connector outputs a TTL signal that has the same duration as the calibrated switching time of the filter. This signal can be used, for example, to monitor the switching time and to cause events to coincide with or follow the switching event, such as imaging or shuttering.

The Analog In connector allows the center wavelength to be set by a 0 to 5 V signal from an external voltage source and changed by an internal or external trigger. 0 V corresponds to the minimum wavelength of 420 nm or 650 nm, while 5 V corresponds to the maximum wavelength of 730 nm or 1100 nm.

Kurios' Sequence Preload Function, which is accessible from the front panel, the included GUI, and a command-line interface, permits the user to define a sequence of wavelengths (up to 1024 values). Providing an internal or external trigger switches the wavelength to the next value in the sequence. This function can be used, for example, in combination with the Trigger Out and Trigger In connectors to trigger a camera at the completion of each wavelength switch and then accept a trigger from the camera once the image is obtained. This sequence is stored within the controller's non-volatile memory, enabling the user to close the software GUI or unplug the USB cable without loss of the preloaded sequence. However, powering off the controller will cause the non-volatile memory to reset.

The Bandwidth button on the front of the controller toggles through various operating modes. For the KURIOS-VB1(/M), this button toggles between Narrow, Medium, and Wide (the three selectable bandwidths), as well as beam-blocking mode ("Black"). For the fixed bandwidth models, the Bandwidth button toggles between the only bandwidth available and Black mode. 

Visible Wavelength Fixed Wide Bandwidth Liquid Crystal Tunable Filter

• Wavelength Range: 420 - 730 nm
• Bandwidth at λ 550 nm: 35 nm FWHM
• Switching Time: <50 ms
• Polarized Transmission: 45%

ThorLabs offers two options for fixed wide-bandpass liquid crystal tunable filters in the visible wavelength: the KURIOS-WB1 (20mm aperture) and the KURIOS-WL1 (35mm aperture). To eliminate transmission in the near-IR and IR wavelength range, each of these tunable filters includes a premium shorpass filter with a 750nm cut-off wavelength in an SM-threaded housing. The switching times vary depending on the initial and final wavelengths, with greater changes to the CWL causing switching times to increase up to a max of 40 ms. Each filter is factory calibrated and ships with a switching time map so that users can optimize their system for the specific filter.

Visible Wavelength Fixed Narrow Bandwidth Liquid Crystal Tunable Filter

• Wavelength Range: 420 - 730 nm
• Bandwidth at λ 550 nm: 10 nm FWHM
• Switching Time: <70 ms
• Polarized Transmission: 45%

ThorLabs offers a fixed narrow-bandpass liquid crystal tunable filter in the visible wavelength. The transmission and width of the bandpass region increase with the CWL (between 430-730nm). To eliminate transmission in the near-IR and IR wavelength range, this tunable filter features a premium shortpass filter with a 750nm cut-off wavelength in an SM2-threaded housing. 

The fixed narrow bandpass tunable filter provides switching times that vary depending upon the initial and final wavelengths. For small changes in the CWL (Δλ ≤ 30 nm), the switching time will be ≤10 ms. For greater changes in the CWL, the switching time will increase, reaching a maximum of 70 ms when switching from 425 nm to 725 nm.

This filter features a clear aperture of 35mm. 

VIS Wavelength Selectable Bandwidth Liquid Crystal Tunable Filter

• Wavelength Range: 420 - 730 nm
• Bandwidth at λ = 550 nm:
  • Narrow Setting: 10 nm FWHM
  • Medium Setting: 18 nm FWHM
  • Wide Setting: 32 nm FWHM
• Switching Time Depends Upon Bandwidth and Initial and Final Wavelength:
  • Narrow Setting: <230 ms
  • Medium Setting: <150 ms
  • Wide Setting: <100 ms
• Polarized Transmission:
  • Narrow Setting: 13%
  • Medium Setting: 17%
  • Wide Setting: 20%

The ThorLabs KURIOS-VB1 is a selectable bandwidth version of the Kurios VIS LCTF. The center wavelength is tunable from 420-730 nm and the bandwidth can be set as either Narrow, Medium or Wide. For a given setting, the transmission and the width of the bandpass region increases with the CWL. The KURIOS-VB1 includes a premium shortpass filter to eliminate transmission in the NIR and IR wavelength range. Switching time depends on the bandwidth setting and inital and final wavelengths. Max switching time is 230 ms for the Narrow setting, 150 ms for the Medium setting, and 100 ms for the wide setting. Switching time will be longer for greater changes in wavelength. Each Kurios filter is factory calibrated and shipped with a switching time map so that the user can optimize their system for the specific filter.

NIR Wavelength Fixed Bandwidth Liquid Crystal Tunable Filter

• Wavelength Range: 650 - 1100 nm
• Bandwidth at λ = 850 nm: 17 nm FWHM
• Switching Time: <250 ms
• Polarized Transmission: 44%

The ThorLabs KURIOS-XE2 is a fixed bandpass Kurios tunable bandpass filter for near-IR wavelengths. The CWL is tunable from 650-1100 nm. Switching times of this fixed bandpass tunable filter depends on the initial and final wavelengths, greater changes to the CWL will increase switching times to a max of 250 ms.

This filter is available with a 20 mm aperture and is factory calibrated, and shipped with a switching time map to allow users to optimize their system for the specific filter.