LBTEK Laser Mode Converter (LMC) is fabricated from N-BK7 window substrates and liquid crystal polymer (LCP) material. Using optical alignment technology, patterned LCP thin films with different fast-axis distributions are formed on the glass surface. By precisely controlling the film thickness, the phase retardation between the ordinary (o) and extraordinary (e) rays in the liquid crystal molecules is set to π, making it a single-wavelength device.

The LBTEK Laser Mode Converter is a diffractive optical element that, through its specific structure and phase distribution, enables the conversion of a fundamental TEM₀₀ mode into higher-order Hermite–Gaussian modes. Different structural and phase distribution designs allow different mode conversions. LBTEK offers standard converters for TEM₀₀ → TEM₁₀ / TEM₀₁ and TEM₀₀ → TEM₁₁ transformations, with available operating wavelengths of 532 nm, 633 nm, 780 nm, and 1064 nm. All converters are mounted in a black anodized standard SM1 lens tube engraved with the fast-axis orientation, product model, and specifications for easy identification and use.

LBTEK Mode Converter is fabricated on an N-BK7 window with a double-substrate structure and a total thickness of 3.2 mm. It provides a uniform phase retardation of λ/2 across the entire clear aperture at the design wavelength. The TEM₀₀–TEM₁₁ mode converter divides the glass into four regions. The fast-axis orientations in two diagonal regions are identical, while those in adjacent regions are orthogonal, resulting in a phase difference of π.

The converter is mounted in a black anodized standard SM1 lens tube, which is engraved with the product model and specifications. On the end face, a vertical line and a dot are marked: the vertical line indicates the 0° fast-axis direction, and the region corresponding to the dot has its fast axis parallel to the vertical line, while the adjacent region has its fast axis perpendicular (as illustrated, the fast axis in the upper right region and its diagonal counterpart is 0°, while that in the upper left region and its diagonal counterpart is 90°).