{"product_id":"thz-detector-crystals-mounted","title":"Mounted THz Detector Crystals for Electro-Optic Sampling","description":"\u003ch2\u003eOverview\u003c\/h2\u003e\n\u003cp\u003eThese are electro-optic sampling crystals supplied ready-mounted in a carrier, so the fragile thin element is protected and can be dropped straight into a standard optic holder. Very thin electro-optic crystals are difficult to handle unmounted; pre-mounting removes the most common cause of breakage during a first build and makes the detection arm repeatable between users.\u003c\/p\u003e\n\u003ch2\u003eHow electro-optic sampling works\u003c\/h2\u003e\n\u003cp\u003eThe terahertz electric field induces a transient birefringence in the crystal. A co-propagating femtosecond probe pulse therefore picks up a small polarisation rotation proportional to the instantaneous terahertz field. A quarter-wave plate biases the probe to circular polarisation, a Wollaston prism splits it into two orthogonal components, and a balanced photodetector reads the difference. Scanning the probe delay reconstructs the field waveform in time, and the Fourier transform gives amplitude and phase together.\u003c\/p\u003e\n\u003ch2\u003eThickness sets the trade-off\u003c\/h2\u003e\n\u003cp\u003eA thicker crystal gives a longer interaction length and a larger signal, but the velocity match between the optical group velocity and the terahertz phase velocity holds over a narrower frequency range, so high-frequency components wash out. Thin crystals do the opposite. Choose thickness against the bandwidth the experiment actually needs rather than defaulting to the largest signal.\u003c\/p\u003e\n\u003ch2\u003eAlignment notes\u003c\/h2\u003e\n\u003cp\u003eOverlap the terahertz focus and the probe focus on the same spot, keeping the terahertz spot larger than the probe so the probe samples a uniform field. Electro-optic crystals are not rotationally symmetric: rotate the crystal about the beam axis to maximise the differential signal before optimising anything else. Keep the crystal inside the purged volume with the rest of the terahertz path.\u003c\/p\u003e\n","brand":"Swiss Terahertz","offers":[{"title":"Default Title","offer_id":48987922530458,"sku":"SWT-DETXTAL","price":0.0,"currency_code":"SGD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0734\/6156\/3546\/files\/SWT-DETXTAL-card-square_bcc08922-0a41-451b-912d-fdfc1be05af2.jpg?v=1786343891","url":"https:\/\/waveqvanta.com\/products\/thz-detector-crystals-mounted","provider":"WaveQuanta","version":"1.0","type":"link"}