CN205384407U - Reflective digital holographic microscope of dual wavelength - Google Patents

Abstract

The utility model discloses a reflective digital holographic microscope of dual wavelength, including first laser instrument, second laser instrument, cube beam splitter prism, optical distance extender, first speculum, dispersion prism, cube beam combining prism and camera device, still include the second mirror, achromatic lens, achromatic microscope objective and sample platform. The utility model is used for the micro - formation of image of reflective the sample surface 3D, the light path of laser beam sharing and the optical element of two bundles of different wavelength for the device structure is simple relatively, and manufacturing cost is lower, and is simpler during the use, convenient to popularize and use.

Description

A dual-wavelength reflective digital holographic microscope

technical field

The utility model relates to the technical field of digital holographic imaging, in particular to a dual-wavelength reflective digital holographic microscope.

Background technique

Digital Holography (Digital Holography) is the product of the combination of ordinary holography, computer technology, and electronic imaging technology. The recording process of digital holography and ordinary holography is basically the same, the difference is that CCD, CMOS and other electronic imaging devices are used instead of holographic dry plates to record holograms, and the recorded holograms are stored in the computer. The reproduction process of digital holography is also different from that of ordinary holography. It uses numerical calculation methods to perform holographic reproduction on holograms stored in computers. Compared with ordinary holography, digital holography has the following advantages:

(1) Since the electronic imaging device is used to replace the holographic dry plate to record the hologram, the required exposure time can be very short, without the wet processing process of the chemical silver salt dry plate, it can continuously record the various instantaneous processes of the moving object, and realize video recording. continuous real-time online holographic recording;

(2) Quantitative images of the intensity distribution and phase distribution of the object light wave can be simultaneously obtained through digital reconstruction.

Digital holographic microscope is the product of the combination of digital holographic technology and microscopic imaging technology, which can perform microscopic imaging of tiny objects, and has important application prospects in biomedicine and other fields. The working process of the existing digital holographic microscope is divided into two steps, one is to use CCD or CMOS to record the hologram formed by light wave interference, and then store the hologram in the computer; the other is to use the computer to simulate the optical diffraction process, through numerical calculation To realize the holographic reproduction of the recorded object. Through holographic reconstruction, the magnitude image and phase image of the recorded object can be obtained at the same time, and the phase image contains the three-dimensional information of the recorded object, so most applications use the phase image.

Because no matter how much the phase difference of the two light waves participating in the interference is, the phase value obtained by the holographic reconstruction algorithm is between between, so there exists what is called the wrapped phase or Uncertain phase problem. In order to obtain the real phase image of the recorded object, phase unwrapping must be performed. However, due to the occurrence of discontinuities or mutations, at the point of discontinuities or mutations, errors in phase unwrapping occur. In order to more effectively unwrap the phase of discontinuous or abrupt points, someone proposed a dual-wavelength digital holography technology, which uses laser beams with two wavelengths to record holograms, and uses the wrapped phase images corresponding to the two wavelengths to jointly perform Phase unwrapping.

Dual-wavelength digital holographic technology, compared with single-wavelength digital holographic technology, in the holographic recording device, the following two issues should be considered: one is to ensure that the same position pixel of the package phase image corresponding to the two wavelengths corresponds to the same point of the sample The second is to ensure that the directions of the holographic interference fringes corresponding to the two wavelengths have a relatively large angle, so that in the Fourier spectrum of the dual-wavelength composite hologram, the primary components corresponding to the two wavelengths are separated as much as possible. In order to meet the above conditions, the current dual-wavelength digital holographic recording device is too complicated (Jonas Kühn, Tristan Colomb, Frédéric Montfort, Florian Charrière, Yves Emery, Etienne Cuche, Pierre Marquet, and Christian Depeursinge. Real-time dual-wavelength digital holographic microscopy with asingle hologram acquisition [J]. :7231-7242.), which is not conducive to popularization and application.

Utility model content

The purpose of this utility model is to solve the defects of the prior art and provide a dual-wavelength reflective digital holographic microscope for 3D microscopic imaging of reflective sample surfaces. The technical scheme adopted is as follows:

A dual-wavelength reflective digital holographic microscope, including a first laser, a second laser, a cubic beam splitting prism, an optical path extender, a first reflector, a dispersion prism, a cubic beam combining prism, and an imaging device, and also includes a second reflection mirror, achromat lens, achromat microscope objective lens, sample stage and computer; wherein, the relative positions of the first reflector, dispersion prism and cubic beam combining prism make the directions of the holographic interference fringes corresponding to the two wavelengths respectively inconsistent; the first The laser and the second laser output two beams of different wavelengths, and the two beams are respectively injected into the cubic beam splitting prism along the normal direction of two different sides of the cubic beam splitting prism, and from the normal of the other two sides of the cubic beam splitting prism Each direction emits a beam of dual-wavelength mixed laser beams; one of them is a reference beam, and the reference beam is reflected into the dispersion prism by the optical path extender and the first mirror, and the dispersion prism separates the beam into two beams with slightly different propagation directions. The single-wavelength laser beam, the two single-wavelength laser beams are injected into a cubic beam-combining prism together, and then injected into the camera device; the other beam is the object beam, which is reflected by the second reflector into the cubic beam-combining prism, and then The achromatic lens and the achromatic microscopic objective lens irradiate the sample placed on the sample stage, and the light reflected by the sample enters the cubic beam combining prism through the achromatic microscopic objective lens and the achromatic lens, and the sample is imaged to the image transmission device of the imaging device. The sensing surface interferes with the reference beam to form a dual-wavelength compound hologram; after the hologram is captured by the camera device, it is stored in the computer for holographic reproduction.

In the utility model, the achromatic microscopic objective lens, the achromatic lens and the sample stage can be appropriately moved and adjusted along the optical axis direction, so that the image surface of the achromatic microscopic objective lens and the achromatic lens to the sample is located on the image sensing surface of the imaging device Above; the optical path extender is adjustable, so that the optical path difference between the reference beam and the object beam reaching the image sensing surface of the imaging device is smaller than the coherence length of the laser.

Preferably, the first laser and the second laser are arranged at intervals of 90 degrees.

Preferably, the utility model also includes a first spatial light filter and a first beam expander collimating lens arranged sequentially between the first laser and the cubic beam splitting prism, and sequentially arranged between the second laser and the cubic beam splitting prism The second spatial light filter and the second beam expander collimating lens.

The spatial light filter and the beam expander and collimator lens respectively filter and expand the beam and collimate the beam emitted by the laser.

Preferably, the rear focal point of the achromatic microscope objective lens coincides with the front focal point of the achromatic lens to form a combined optical system.

Preferably, the achromatic lens is a positive lens.

Compared with the prior art, the utility model has the beneficial effects:

The utility model is used for 3D microscopic imaging of reflective sample surfaces. Two laser beams with different wavelengths share one optical path and optical elements, so that the device structure is relatively simple, the manufacturing cost is lower, and the use is simpler, which is convenient for popularization and use.

Description of drawings

Fig. 1 is a structural representation of the utility model.

detailed description

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail.

Embodiment: As shown in Figure 1, a dual-wavelength reflective digital holographic microscope includes a first laser 1, a second laser 2, a cubic beam splitting prism 7, an optical path extender 8, a first reflecting mirror 9, and a dispersion prism 10. Cube beam combining prism 11 and imaging device 17 also include second reflector 12, achromatic lens 13, achromatic microscope objective lens 14 and sample stage 16, wherein, first reflector 9, dispersion prism 10 and cube combiner The relative position of the beam prism 11 makes the directions of the holographic interference fringes corresponding to the two wavelengths inconsistent. The first laser 1 and the second laser 2 output two beams of different wavelengths, and the two beams are respectively along two different sides of the cubic beam splitting prism 7. The normal direction of the beam-splitting prism is injected into the cubic beam-splitting prism 7, and a beam of dual-wavelength mixed laser beams is respectively emitted from the normal direction of the other two sides of the cubic beam-splitting prism 7, one of which is a reference beam, and the reference beam passes through The optical path extender 8 and the first reflector 9 are reflected into the dispersion prism 10, and the dispersion prism 10 separates the light beam into two single-wavelength laser beams with slightly different propagation directions, and the two single-wavelength laser beams are injected into a cubic beam combining prism together 11, and then shoot into the imaging device 17; the other beam is the object beam, which is reflected by the second mirror into the cubic beam combining prism 11, and then irradiated by the achromatic lens 13 and the achromatic microscope objective lens 14 and placed on the sample stage On the sample 15, the light reflected by the sample is injected into the cubic beam combining prism 11 through the achromatic microscope objective lens 14 and the achromatic lens 13, and the sample 15 is imaged onto the image sensing surface of the imaging device 17 to interfere with the reference beam , to form a dual-wavelength composite hologram; after the hologram is photographed by the imaging device 17, it is stored in the computer 18 for holographic reproduction.

In this embodiment, the achromatic microscopic objective lens 14, the achromatic lens 13, and the sample stage 16 can be moved and adjusted appropriately along the optical axis direction, so that the image plane of the achromatic microscopic objective lens 14 and the achromatic lens 13 to the sample is positioned at the imaging device. 17 on the image sensing surface; the optical path extender 8 is adjustable, so that the optical path difference between the reference beam and the object beam reaching the image sensing surface of the imaging device is smaller than the coherence length of the laser.

The first laser 1 and the second laser 2 are arranged at an interval of ninety degrees.

This embodiment also includes a first spatial light filter 3 and a first beam expander collimating lens 5 arranged sequentially between the first laser 1 and the cubic beam splitter 7, and sequentially arranged between the second laser 2 and the cubic beam splitter prism 7 between the second spatial light filter 4 and the second beam expander collimating lens 6 .

The spatial light filter and the beam expander and collimator lens respectively filter and expand the beam and collimate the beam emitted by the laser.

In this embodiment, the rear focal point of the achromatic microscope objective lens 14 coincides with the front focal point of the achromatic lens 13 to form a combined optical system.

In this embodiment, the achromatic lens 13 is a positive lens.

In this embodiment, the first laser 1 is a red helium-neon laser with an output power of 3mW and a wavelength of λ=632.8nm; the second laser 2 is a yellow helium-neon laser with an output power of 3mW and a wavelength of λ=594nm; Spatial filters 3 and 4 are composed of pinholes and 20 times microscope objective lenses; beam expander collimating lenses 5 and 6 are K9 glass plano-convex lenses with a focal length of 60 mm and a diameter of 30 mm; cubic beam splitting prism 7 and cubic beam combining prism 11 adopt K9 glass cube dichroic prism with an edge length of 25.4mm and a splitting ratio of 1:1; the optical path extender 8 is composed of four K9 glass silver-coated flat mirrors with a diameter of 40mm; the dispersion prism 10 is a prism with an edge length of 25.4mm K9 glass 45 degree equilateral triangular prism; reflector 9 and 12 are flat reflectors of K9 glass silver-plated and diameter 40mm; The micro-objective lens 14 is an apochromatic objective lens; the imaging device 17 is a CCD camera.

Claims (5)

1. A dual-wavelength reflective digital holographic microscope, characterized in that it comprises a first laser, a second laser, a cubic beam splitting prism, an optical path extender, the first reflector, a dispersion prism, a cubic beam combining prism and an imaging device , also includes a second mirror, an achromatic lens, an achromatic microscope objective, a sample stage and a computer; wherein, the relative positions of the first mirror, the dispersion prism and the cubic beam combining prism make the holographic interference fringes corresponding to the two wavelengths respectively The directions are inconsistent; the first laser and the second laser output two beams with different wavelengths, and the two beams are respectively injected into the cubic beam-splitting prism along the normal directions of two different sides of the cubic beam-splitting prism, and from the other side of the cubic beam-splitting prism The normal direction of the two sides emits a beam of dual-wavelength mixed laser beams respectively; one of them is a reference beam, and the reference beam is reflected into the dispersive prism by the optical path extender and the first reflector, and the dispersive prism separates the beam into propagation Two single-wavelength laser beams with slightly different directions, the two single-wavelength laser beams are injected into a cubic beam combining prism together, and then injected into the imaging device; the other beam is the object beam, and the object beam is reflected into the cube by the second reflector. The beam-combining prism irradiates the sample placed on the sample stage through the achromatic lens and the achromatic microscope objective lens, and the light reflected by the sample enters the cubic beam-combining prism through the achromatic microscope objective lens and the achromatic lens to image the sample The image sensing surface of the imaging device interferes with the reference beam to form a dual-wavelength composite hologram; after the hologram is captured by the imaging device, it is stored in the computer for holographic reproduction. 2 . The dual-wavelength reflective digital holographic microscope according to claim 1 , wherein the first laser and the second laser are arranged at an interval of 90 degrees. 3. A dual-wavelength reflective digital holographic microscope according to claim 1, further comprising a first spatial light filter and a first beam expander sequentially arranged between the first laser and the cubic beam splitting prism The collimator lens is a second spatial light filter and a second beam expander collimator lens arranged sequentially between the second laser and the cubic beam splitting prism. 4. A dual-wavelength reflective digital holographic microscope according to claim 1, characterized in that the rear focal point of the achromatic microscope objective coincides with the front focal point of the achromatic lens to form a combined optical system. 5. A dual-wavelength reflective digital holographic microscope according to claim 1, wherein the achromatic lens is a positive lens.