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Han M, Smith D, Kahro T, Stonytė D, Kasikov A, Gailevičius D, Tiwari V, Ignatius Xavier AP, Gopinath S, Ng SH, John Francis Rajeswary AS, Tamm A, Kukli K, Bambery K, Vongsvivut J, Juodkazis S, Anand V. Extending the Depth of Focus of an Infrared Microscope Using a Binary Axicon Fabricated on Barium Fluoride. MICROMACHINES 2024; 15:537. [PMID: 38675348 PMCID: PMC11052387 DOI: 10.3390/mi15040537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/05/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024]
Abstract
Axial resolution is one of the most important characteristics of a microscope. In all microscopes, a high axial resolution is desired in order to discriminate information efficiently along the longitudinal direction. However, when studying thick samples that do not contain laterally overlapping information, a low axial resolution is desirable, as information from multiple planes can be recorded simultaneously from a single camera shot instead of plane-by-plane mechanical refocusing. In this study, we increased the focal depth of an infrared microscope non-invasively by introducing a binary axicon fabricated on a barium fluoride substrate close to the sample. Preliminary results of imaging the thick and sparse silk fibers showed an improved focal depth with a slight decrease in lateral resolution and an increase in background noise.
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Affiliation(s)
- Molong Han
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (M.H.); (D.S.); (S.H.N.); (S.J.)
| | - Daniel Smith
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (M.H.); (D.S.); (S.H.N.); (S.J.)
| | - Tauno Kahro
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Dominyka Stonytė
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, 10223 Vilnius, Lithuania; (D.S.); (D.G.)
| | - Aarne Kasikov
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Darius Gailevičius
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, 10223 Vilnius, Lithuania; (D.S.); (D.G.)
| | - Vipin Tiwari
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Agnes Pristy Ignatius Xavier
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
- School of Electrical and Computer Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer-Sheva 8410501, Israel
| | - Shivasubramanian Gopinath
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Soon Hock Ng
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (M.H.); (D.S.); (S.H.N.); (S.J.)
| | | | - Aile Tamm
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Kaupo Kukli
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
| | - Keith Bambery
- Infrared Microspectroscopy (IRM) Beamline, ANSTO—Australian Synchrotron, Clayton, VIC 3168, Australia (J.V.)
| | - Jitraporn Vongsvivut
- Infrared Microspectroscopy (IRM) Beamline, ANSTO—Australian Synchrotron, Clayton, VIC 3168, Australia (J.V.)
| | - Saulius Juodkazis
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (M.H.); (D.S.); (S.H.N.); (S.J.)
- Tokyo Tech World Research Hub Initiative (WRHI), School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Vijayakumar Anand
- Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (M.H.); (D.S.); (S.H.N.); (S.J.)
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia; (T.K.); (A.K.); (V.T.); (A.P.I.X.); (S.G.); (A.S.J.F.R.); (A.T.); (K.K.)
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Bleahu AI, Gopinath S, Kahro T, Angamuthu PP, John Francis Rajeswary AS, Prabhakar S, Kumar R, Salla GR, Singh RP, Kukli K, Tamm A, Rosen J, Anand V. 3D incoherent imaging using an ensemble of sparse self-rotating beams. OPTICS EXPRESS 2023; 31:26120-26134. [PMID: 37710480 DOI: 10.1364/oe.493526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/29/2023] [Indexed: 09/16/2023]
Abstract
Interferenceless coded aperture correlation holography (I-COACH) is one of the simplest incoherent holography techniques. In I-COACH, the light from an object is modulated by a coded mask, and the resulting intensity distribution is recorded. The 3D image of the object is reconstructed by processing the object intensity distribution with the pre-recorded 3D point spread intensity distributions. The first version of I-COACH was implemented using a scattering phase mask, which makes its implementation challenging in light-sensitive experiments. The I-COACH technique gradually evolved with the advancement in the engineering of coded phase masks that retain randomness but improve the concentration of light in smaller areas in the image sensor. In this direction, I-COACH was demonstrated using weakly scattered intensity patterns, dot patterns and recently using accelerating Airy patterns, and the case with accelerating Airy patterns exhibited the highest SNR. In this study, we propose and demonstrate I-COACH with an ensemble of self-rotating beams. Unlike accelerating Airy beams, self-rotating beams exhibit a better energy concentration. In the case of self-rotating beams, the uniqueness of the intensity distributions with depth is attributed to the rotation of the intensity pattern as opposed to the shifts of the Airy patterns, making the intensity distribution stable along depths. A significant improvement in SNR was observed in optical experiments.
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Kumar R, Anand V, Rosen J. 3D single shot lensless incoherent optical imaging using coded phase aperture system with point response of scattered airy beams. Sci Rep 2023; 13:2996. [PMID: 36810914 PMCID: PMC9944900 DOI: 10.1038/s41598-023-30183-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 02/17/2023] [Indexed: 02/23/2023] Open
Abstract
Interferenceless coded aperture correlation holography (I-COACH) techniques have revolutionized the field of incoherent imaging, offering multidimensional imaging capabilities with a high temporal resolution in a simple optical configuration and at a low cost. The I-COACH method uses phase modulators (PMs) between the object and the image sensor, which encode the 3D location information of a point into a unique spatial intensity distribution. The system usually requires a one-time calibration procedure in which the point spread functions (PSFs) at different depths and/or wavelengths are recorded. When an object is recorded under identical conditions as the PSF, the multidimensional image of the object is reconstructed by processing the object intensity with the PSFs. In the previous versions of I-COACH, the PM mapped every object point to a scattered intensity distribution or random dot array pattern. The scattered intensity distribution results in a low SNR compared to a direct imaging system due to optical power dilution. Due to the limited focal depth, the dot pattern reduces the imaging resolution beyond the depth of focus if further multiplexing of phase masks is not performed. In this study, I-COACH has been realized using a PM that maps every object point into a sparse random array of Airy beams. Airy beams during propagation exhibit a relatively high focal depth with sharp intensity maxima that shift laterally following a curved path in 3D space. Therefore, sparse, randomly distributed diverse Airy beams exhibit random shifts with respect to one another during propagation, generating unique intensity distributions at different distances while retaining optical power concentrations in small areas on the detector. The phase-only mask displayed on the modulator was designed by random phase multiplexing of Airy beam generators. The simulation and experimental results obtained for the proposed method are significantly better in SNR than in the previous versions of I-COACH.
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Affiliation(s)
- Ravi Kumar
- School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, P.O. Box 653, 8410501, Beer-Sheva, Israel.
- Department of Physics, SRM University-AP, Amaravati, Andhra Pradesh, 522502, India.
| | - Vijayakumar Anand
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411, Tartu, Estonia
- Optical Sciences Center, Swinburne University of Technology, Hawthorn, Melbourne, VIC, 3122, Australia
| | - Joseph Rosen
- School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, P.O. Box 653, 8410501, Beer-Sheva, Israel
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411, Tartu, Estonia
- Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, 7600, South Africa
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