JPS63133182A - Method and device for measuring interference of minute phase object - Google Patents

Abstract

PURPOSE:To obtain phase difference intensifying information of a minute phase object by introducing the phase difference intensifying method based on holography to a Mach-Zehnder interferometer having the intensifying function. CONSTITUTION:An objective lens 36 is inserted to an optical path II where a sample 35 is placed of the Mach-Zehnder interfereometer to constitute a microscope. An objective lens 37 is arranged in an optical path I so that interference fringes on a hologram become linear diffraction grating. A hologram recording medium 38 is set on the image surface position of the objective lens to form an image surface hologram. At this time, a semitransparent mirror 32 is inclined at an angle alpha/2 to make an angle alpha between the object light and the reference light so that orders of reproduced waves of the hologram do not overlap in the same position, thus separating diffracted waves at the time of hologram reproducing. Thus, phase difference intensifying information of the minute phase object is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring the interference of a minute phase object, which makes it possible to observe a minute phase object using a phase difference expansion method using holography.

[Conventional technology]

FIG. 4 is a diagram showing a Matsuhatsu Ender interferometer used as a conventional phase object observation method.

In the figure, 1.2 is a semi-transparent mirror, 3.4 is a reflecting mirror, 5 is a screen, and 6 is an eye.

In the figure, light rays from the same light source are divided into two optical paths by a semi-transparent mirror 1, and the light rays passing through optical paths (2) and (2) are caused to interfere on a screen 5 via the semi-transparent mirror 2, and the interference fringes are observed. In this case, if a phase object is placed on the optical path I or H, interference fringes based on the optical path without the phase object are formed on the observation plane, and phase information can be obtained.

By the way, with the interferometer shown in FIG. 4, it is impossible to observe minute objects as is. Therefore, by incorporating an interferometer into a microscope as shown in FIG. 5, it is possible to observe minute phase objects.

FIG. 5 is a diagram showing such a conventional interference microscope, in which 11 is a beam splitter, 12 is a sample, 13 is a beam combiner,
14 is an objective lens.

In the figure, the beam splitter 11 divides the light into optical paths ■ and ■, and the light passes through the phase object sample 12 placed in the optical path ■ and the optical path I
By making the light incident on the objective lens 14 via the beam coupler 13, interference fringes are formed on the magnified phase object with the optical path I as a reference, and are observed through an eyepiece (not shown).

FIG. 6 is a diagram showing another example of a conventional interference microscope.
21 to 24 are beam splitters, 25.26 are condensing lenses, 2
7.28 is a plate glass, and 29.30 is an objective lens.

Figure 6 shows that a very narrow area of a plate glass sample is illuminated with a spherical wave using condenser lenses 25 and 26, and the optical path
The fifth exception was that the observation was made with and ■ as equal conditions.
It is exactly the same as the one shown in the figure.

[Problem that the invention seeks to solve]

However, even if conventional interference microscopes use holography to perform phase difference expansion to observe minute phase objects, the reproduced waves of the same order of the hologram used for phase difference expansion all overlap at the same position, making observation difficult. It is not possible to form a hologram that is effective for expanding the phase difference on the hologram recording surface.

The present invention is intended to solve the above-mentioned problems, and provides a microphase object interferometry method and apparatus that can obtain phase difference expansion information of a microphase object using a phase difference expansion method using holography. With the goal.

[Means for solving problems]

To this end, the microphase object interferometry method and apparatus of the present invention records a hologram by setting an appropriate angle between the object beam and the reference beam of the interference microscope, and makes the two reproduction optical paths incident on the hologram surface. Irradiate the reproduction light at different angles,
By reproducing the hologram by aligning diffracted lights of arbitrary orders with different signs that have passed through the hologram surface at a predetermined point, the phase difference can be enlarged for observation;
and a first semi-transparent mirror arranged such that an objective lens is arranged, one of which receives the passing light of the two optical paths on which the sample is placed, and the reflected light and the transmitted light form a predetermined angle. A hologram recording means, a second semi-transparent mirror arranged such that the 1lTl transmitted light of the two optical paths is incident, and the reflected light and the transmitted light form a predetermined angle, and the reflected light and the transmitted light from the second semi-transparent mirror. a hologram recording medium into which the light is incident, a lens system that matches diffracted light of arbitrary orders with different signs from the hologram recording medium at a predetermined position, an aperture means having a pinhole disposed at the predetermined position, and a pinhole. It is characterized by comprising a hologram reproducing means equipped with a means for observing a transmitted image.

[Effect]

The present invention records a hologram by setting an appropriate angle between the object beam and the reference beam of an interference microscope, and irradiates the reproduction light with different incident angles on the hologram surface of two reproduction optical paths. By reproducing the hologram by aligning the diffracted lights of arbitrary orders with different signs that have passed through the hologram surface at a predetermined point, it becomes possible to obtain phase difference expansion information of a minute phase object.

〔Example〕

Examples will be described below based on the drawings.

The minute phase object interferometry method of the present invention uses holography and therefore consists of two steps: recording and reproduction.

FIG. 1 is a diagram showing the configuration of a hologram recording device used in the Hui small phase object interferometry method according to the present invention.
32 is a semi-transparent mirror, 33.34 is a reflective mirror, 35 is a sample, 36
．． 37 is an objective lens, and 38 is a hologram recording medium.

In the figure, a microscope is constructed by inserting an objective lens 36 into the optical path (2) in which a sample 35 of a Matsuhatsu Ender interferometer is placed. At the same time, the objective lens 37 is placed in the optical path (2) so that the interference fringes on the hologram become a linear diffraction grating. Further, a hologram recording medium 38 is set at the image plane position of the objective lens to form an image plane hologram.

By tilting the half-transparent mirror 32 at an angle α/2, an angle α is created between the object beam and the reference beam, so that the orders of the hologram reproduction waves do not all overlap at the same position, and the diffracted waves during hologram reproduction are Allows for separation.

FIG. 2 is a diagram showing the configuration of a hologram reproduction device used in the microphase object interferometry method according to the present invention.
42 is a semi-transparent mirror, 43.44 is a reflective mirror, 45 is a hologram recording medium, 46.47.48 is a lens, 49 is an aperture, A, D are 0th order light, B, E are +1st order diffracted light, C, F
is the first-order diffracted light.

In the figure, by tilting the semi-transparent mirror 42, the 0th-order light A, +1
The 0th-order diffracted light D, the −1st-order diffracted light C, and the 0th-order diffracted light D, the +1st-order diffracted light E, and the −1st-order diffracted light C are the 0th-order light D, the +1st-order diffracted light E, and the −
It is separated from the first-order diffracted light F. At this time, by adjusting the angle of the semi-transparent mirror 42, the 1st-order diffracted light C and the +1st-order diffracted light E can be made to coincide on the pinhole of the aperture 49, as shown in the figure, and this image is transferred to the lens 47. .48
Observe through.

It will be explained with reference to FIG. 3 that the above operation doubles the phase difference and obtains twice the number of interference fringes compared to conventional interferometry.

FIG. 3 is a diagram for explaining the phase difference expansion of the micro-phase object interferometry method according to the present invention, in which (a) is the interference pattern obtained by a conventional interference microscope, and the figure (opening) is the interference pattern according to the present invention. In the figure, 51 is a phase reference plane, 52 is a wavefront,
53 is the +1st-order reproduced wavefront, 54 is the 11th-order reproduced wavefront, 5
5 is a position where interference fringes are formed.

With a conventional interference microscope, only the actual phase difference information of a phase object, that is, the wavefront 52 relative to the phase reference plane 51 as shown in FIG. 3(a), can be obtained, but as shown in FIG. By obtaining an image in which the −1st-order diffracted light is aligned, −
Since the first-order reproduced wavefronts are added together, twice as much phase difference information is obtained and twice as many interference fringes are obtained.

Note that the interference fringe spacing can be arbitrarily selected by selecting the angle of the semi-transparent mirror 42, so if the fringe spacing is the same as in Figure 3 (a), twice the phase difference will appear as a displacement of the fringes. .

In addition, in the above explanation, the diffraction order to be used is +1st order, but if higher order diffraction waves of the same order are used, it is possible to expand by 2 times the order, and the diffraction order is not limited to the same order, but can be any different order. It goes without saying that a diffracted wave of the order may be used.

〔Effect of the invention〕

As described above, according to the present invention, by introducing the phase difference expansion method into a Matsuhatsu Ender interferometer equipped with an expansion function, it becomes possible to obtain phase difference expansion information of a minute phase object.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a hologram recording device used in the micro-phase object interferometry method according to the present invention, and FIG. 2 is a diagram showing the configuration of a hologram reproducing device used in the micro-phase object interferometry method according to the present invention. Fig. 3 is a diagram for explaining the phase difference expansion of the micro phase object interferometry method according to the present invention, in which (a) shows interference fringes by a conventional interference microscope, and (b) shows interference fringes in the conventional interference microscope.
is a diagram showing interference fringes according to the present invention, FIG. 4 is a diagram showing a Matsuhatsu Ender interferometer used as a conventional phase object observation method, FIG. 5 is a diagram showing a conventional interference microscope, and FIG. 6 is a diagram showing a conventional FIG. 3 is a diagram showing another example of the interference microscope. 31.32...Semi-transparent mirror, 33.34...Reflecting mirror, 3
5... Sample, 36.37... Objective lens, 38...
・Holodarum recording medium, 41.42...Semi-transparent mirror, 43
．． 44...Reflecting mirror, 45...Hologram recording medium,
46.47.48...Lens, 49...Aperture, A, D...0th order light, B, E...+1st order diffracted light,
C,, F...-1st order diffracted light, 51... Phase reference plane,
52...Wave surface, 53...+1st-order reproduced wave surface, 54.
... -1st-order reproduced wavefront, 55 ... position where interference fringes are formed.

Claims (4)

[Claims] (1) Record a hologram by setting an appropriate angle between the object beam and reference beam of the interference microscope, and irradiate the reproduction light with different angles of incidence on the hologram surface of the two reproduction optical paths. Microphase object interference characterized in that the hologram is reproduced by reproducing the hologram by matching the diffracted lights of arbitrary orders with different signs that have passed through the hologram surface at a predetermined point, thereby enlarging the phase difference for observation. Measurement method. (2) The microphase object interference measurement method according to claim 1, wherein the object light and the reference light are each incident on the hologram surface via an objective lens. (3) The first semi-transparent mirror is arranged such that an objective lens is arranged, one of which receives the passing light from the two optical paths with the sample placed on it, and the reflected light and the transmitted light form a predetermined angle. a second semi-transparent mirror arranged such that the transmitted light of the two optical paths is incident and the reflected light and the transmitted light form a predetermined angle; and the reflected light from the second semi-transparent mirror. A holographic recording medium into which the transmitted light is incident, a lens system that matches diffracted light of arbitrary orders with different signs from the holographic recording medium at a predetermined position, an aperture means having a pinhole disposed at the predetermined position, and a pin. A microphase object interference measurement device comprising a hologram reproduction means equipped with a hole transmission image observation means. (4) The minute phase object interference measurement device according to claim 3, wherein the second semi-transparent mirror is adjustable in angle.