ABSORPTION MICROSCOPE

PROBLEM TO BE SOLVED: To provide an absorption microscope capable of appropriately recognizing a difference among regions on a sample having a low molar concentration value or on a thin sample in concentration or the like.SOLUTION: A planoconvex lens 17 is formed on at least a back surface of a concave mirror 12 located on a side on which a laser beam as an inspection beam is incident out of concave mirrors 12 and 13 that constitute an optical cavity, so that the inspection beam radiated from the back surface side of the concave mirror 12 can arrive at a collection point P common to the concave mirrors 12 and 13 without refraction. As a result, it is possible to suppress a positional deviation of the collection point P in response to repeated reflection between the concave mirrors 12 and 13 necessary for increasing an optical length, and to improve a spatial resolution of an absorption microscope 1. 【課題】モル濃度の値が低い試料や厚みの少ない試料上の各部位の濃度等の差異を適切に知ることのできる吸収顕微鏡を提供すること。【解決手段】光学キャビティを構成する凹面鏡１２，１３のうち、少なくとも、検査光となるレーザー光の入射側に位置する凹面鏡１２の背面に平凸レンズ１７を形成し、凹面鏡１２の背面側から照射された検査光が屈折を伴わずに凹面鏡１２，１３に共通する集光点Ｐに到達するようにすることで、光路長増幅のために必要とされる凹面鏡１２と凹面鏡１３の間の反射の繰り返しに伴う集光点の位置ずれを抑制し、吸収顕微鏡１における空間分解能を向上させる。【選択図】図１