A tunable broadband laser can emit light over a broad range of wavelengths but can also be tuned to specific wavelengths within that range. An ultra-wide tunable laser can be achieved by combining a supercontinuum laser with a tunable filter. While the supercontinuum laser will generate a spectrum that covers a wide range of wavelengths at once, the tunable filter will add the ability to tune the output of the supercontinuum laser to specific wavelengths and potentially add the benefit of adjusting the bandwidth of the output.
Tunable filters are a crucial component of optical systems that require selection of specific wavelengths or narrow spectral bands of interest. The tunability aspect of these systems makes them versatile and useful in various applications, including spectroscopy, microscopy, telecommunications, and medical imaging.
Types of Tunable Filters
The selection of a tunable filter for a supercontinuum laser depends on the application requirements, and is based on desired tunable range, the number of desired output wavelengths, as well as on the resolution of the output. These are some of the most common types of tunable filters used with supercontinuum white light lasers:
- Variable bandwidth tunable filters. Usually with a single-wavelength output, these budget-friendly filters use a combination of linear variable filters to achieve tunability mostly in the visible range, from 350 nm to 850 nm, and allow bandwidth tunability from 10 nm to 100 nm.
- Acousto-Optic Tunable Filters (AOTFs). These filters use acoustic waves induced by RF signals to change the refractive index of a crystal, allowing for tunable wavelength selection. They offer a wide tunable range and the possibility of multiple tunable output wavelengths simultaneously.
- Grating-based filters. These include devices such as diffraction or other gratings that can be used as tunable filters. They have a wide tunability range and have a narrow linewidth single output.
Modular and Flexible: Leukos’ Compact Broadband Tunable Laser
Leukos supercontinuum lasers and tunable filters are plug-and-play and are designed for effortless coupling with each other via a robust and maintenance-free connection. Their coupling results in a broadband tunable laser source. For example, the output from a SAMBA supercontinuum laser can be combined with a BEBOP tunable filter to achieve tunable output in the visible range up to 850nm.
While the SAMBA line of supercontinuum lasers can output a broadband spectrum from 350 nm to 2400 nm, BEBOP was specially designed for applications that require an tunable output between 350 nm and 850 nm. In the example below, the bandwidth (left panel) was tuned from 10 nm (blue line) to 100 nm (purple line), while the wavelength (right panel) was tuned from 475 nm to 770 nm at a constant linewidth of 20nm. All measurements were performed using a portable visible IndiGo spectrometer with a resolution better than 1.5nm.
To find the best product for your broadband tunable laser needs, you can find more information about Leukos supercontinuum lasers and tunable filters HERE or get in touch with us at [email protected].