Thus, such gratings can be efficiently used to study the spectra of radiation sources, including low-power sources, which is an important capability for studies in the THz frequency range.įor price quotation and delivery please fill in our Request form. The study data for the relief-phase terahertz gratings shows their high optical efficiency and resolution of the operational maxima. Signal was measured with a converging TPX lens. Diffracted monochromatic wave intensity (λ=141 μm) versus diffraction angle for ZEONEX gratings with spacing d=250 μm. Signal was measured with a converging TPX lens.įig. Diffracted monochromatic wave intensity (λ=141 μm) versus diffraction angle for TPX gratings with spacing d=250 μm. Signal was measured without a converging lens.įig. Diffracted monochromatic wave intensity (λ=118 μm) versus diffraction angle for ZEONEX gratings with spacing d=250 μm. Diffracted monochromatic wave intensity (λ=118 μm) versus diffraction angle for TPX gratings with spacing d=250 μm. Due to different radiation sources and optical arrangements used when testing the gratings, intensity below is given in arbitrary units.įig. (First one is in the middle of the transmission band, whereas second one is closer to the edge.) It matches to the theoretical diffracted wave intensities and first-order maxima angles for individual monochromatic waves calculated using Fraunhofer approximation. For example, figures 3-6 show that for TPX and ZEONEX diffraction gratings with 250 μm spacing (transmission band 1.56-3.12 THz, or 96-192 μm) the first-order maxima intensity for a λ=141 μm monochromatic wave is several times greater than for λ=118 μm monochromatic wave. It reaches the maximum in the middle of the range and falls off near its borders. But when spectral lines need to be resolved, the lens becomes necessary.įor a diffraction grating with a specific transmission band determined using the Rayleigh criterion, the diffracted monochromatic wave intensity is wavelength-dependent. When the grating is used to study the properties of the radiation source (power, beam shape, energy distribution etc.), a lens is redundant. It must be taken into account by the users when designing the experiments according to their intent. This is due to focusing parallel beams by the converging lens. Comparison of these plots shows that in the first case zero- and first-order maxima are wider than with lens arrangement. In the second case a converging lens was placed between the grating and radiation sensor. Figures 5 and 6 give monochromatic wave intensity (λ=141 μm) versus diffraction angle for the same gratings illuminated by FEL. Figures 3 and 4 depict monochromatic wave intensity (λ=118 μm) versus diffraction angle for TPX and ZEONEX gratings with spacing d=250 μm, when FIR-laser was used as a radiation source. The second was FEL, a free-electron laser (Siberian Synchrotron and THz Radiation Center, Budker Institute of Nuclear Physics, RAS). The first was FIR-laser, a submillimeter methanol-vapor laser optically pumped by tunable CO 2 laser (Peter the Great St. To validate the operation and compare calculated and actual parameters, characteristics of the gratings were measured in various optical arrangements with different terahertz radiation sources. Gratings parameters, diffracted wave intensities and first-order maxima angles for individual monochromatic waves are calculated using Fraunhofer approximation. Other shapes and sizes are available on demand.ĭepending on the intended application, diffraction gratings can be used in various optical arrangements, with or without converging lenses. THz gratings are usually made square-shaped, 35 mm to 70 mm on a side. The transmissivity spectra of TPX and ZEONEX plates polished on both sides before cutting the grooves are given below.įig. Gratings for other bands within 0.3-3 THz range can be manufactured at customer’s request. The gratings are manufactured in four standard options for the following transmission bands within the 0.3-3 THz range: 0.28–0.55 THz 0.49–0.98 THz 0.87–1.75 THz 1.56–3.12 THz.
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