Thorlabs' THA100 Fast Thermal Sensor Amplified Detector is an amplified, switchable-gain, tetrathiotetracene (TTT) based detector for use with pulsed light signals between 190 nm and 2400 nm. While it is designed for short, high-energy laser pulses, it can also be used to measure modulated or pure continuous wave (CW) sources. A rotary switch on the side of the housing allows for the signal amplification to be adjusted in 8 gain steps up to 36 dB. The signal output is provided via a BNC connector and is capable of driving 50 Ω and high impedance loads with a maximum output voltage of 2 V and 4 V, respectively.
Features
- Wavelength Range: 190 - 2400 nm
- Amplification with Switchable Gain
- Optimized for High-Energy Pulsed or Chopped Light Sources
- 10 ns Typical Rise Time and 800 ns Typical Fall Time
- Detector Active Area: 78.5 mm2 (Ø10 mm)
- External SM1 (1.035"-40) Threads and Internal SM05 (0.535"-40) Threads
Image above: The MPD149-M01 Off-Axis Parabolic Mirror can be used to focus a collimated source in the NIR, making it ideal for use with the THA100 detector.
The outer surface of the THA100 sensor is a thin copper electrode coating which, in combination with the TTT layer below, efficiently absorbs incident photons. This sensor element is built upon submicron thermopile thick film technology whereby the heat flow generated by photon absorption passes perpendicularly through the material layers. The TTT material exhibits an intrinsic Seebeck effect which then converts this thermal energy into electrical energy, resulting in a typical signal rise time of 10 ns and a typical signal fall time of 800 ns. These response times, combined with high power handling and sensitivity, make the detector ideal for monitoring fast manufacturing processes and detecting instabilities in ultrashort laser pulses with repetition rates up to 1 MHz.
Each THA100 detector is shipped with an LDS12B power supply.
The detector's large active area (78.5 mm2) combined with its ability to handle high peak power densities up to 100 kW/cm2 makes it a great choice for measuring light sources with both broad intensity ranges and high peak pulse energies. At gain setting 1 (0 dB), the detector has a sensitivity of 1500 V/J for pulses shorter than 1 µs and 5 mV/W for CW and quasi-CW (QCW) input.
The THA100 detector has a broad absorption wavelength range, from 190 nm to 2400 nm, making it useful for applications with light from UV into MIR wavelengths. For quick reference, the absorption spectrum of the detector is printed on the back of the housing, as shown in Figure 1.3.
The low-profile housing of this detector enables use in optical paths with space constraints. Each housing features external SM1 (1.035"-40) threading, internal SM05 (0.535"-40) threading, and two universal mounting holes that accept both 8-32 and M4 x 0.7 threads, allowing for either vertical or horizontal post mounting. Additionally, an SM1T1 internally SM1-threaded coupler and SM1RR retaining ring are included with each detector, enabling convenient mounting of SM1-compatible accessories, optics, and cage assembly accessories. The internal SM05 threading is only suitable for mating to an externally SM05-threaded lens tube (components such fiber adapters cannot be threaded onto the SM05 threading). Externally SM1-threaded adapters should be mated to the included SM1T1 coupler, while internally SM1-threaded adapters can be mated directly to the housing. When using fiber adapters or other optics, make sure that the components do not crash into the detector.
Thorlabs offers a variety of amplified detectors based on different detector materials that include both free-space and fiber-coupled options.
The back of the THA100 detector displays a sample absorption spectrum.