Reflection-type multiorder grating lens for three ultraviolet wavelengths

Utilization of second-, third-, and fourth-order diffraction is discussed f or providing a single reflection grating lens that yields the same wave-fro nt conversions for wavelengths of 420, 280, and 210 nm, which are used to s ense NOx and SO2 gas densities. A blazed grating lens was fabricated by a p lanar process and characterized by use of UV lamps. The same wave-front con version was observed at the three UV wavelengths. Efficiencies were measure d to be 80%, 70%, and 30% for second-, third-, and fourth-order diffraction s, respectively, at wavelengths of 420, 280, and 210 nm, respectively. (C) 1999 Optical Society of America.