| 摘要 |
<p>An interferometer comprising a beam source (PM, M1, L1) of first and second light beams. The interferometer has a first arm that routes the first light beam via a first pair of mirrors (M4, M5) arranged at right angles to each other in the manner of a corner cube to reverse the direction of the first light beam and a second arm that routes the second light beam via a second pair of mirrors (M2, M3). The beam source (PM, M1, L1) and the second mirror pair (M2, M3) are mounted on a linear translation stage (P1). The first and second light beams are incident on a focusing element (L2) symmetrically about and parallel to its optical axis and then converge at an angle (ζ) to form an interference pattern. The symmetric, balanced configuration of the interferometer is retained under motion of the positioning element, which varies the separation (d) of the first and second light beams on the focusing element. Proximity problems, such as contamination, which result from the use of phase masks in contact mode are avoided. More generally, the interferometer provides a flexible source for large-area, non-focused interference patterns of tuneable period.</p> |
