CN203773151U - S wave plate-based femtosecond laser optical tweezers manipulation device - Google Patents

Abstract

A femtosecond laser optical tweezers control device based on an S-wave plate relates to the optical tweezers technology for optically manipulating particles and cells. It solves the problem that the traditional optical tweezers technology improves the trapping force of the optical tweezers by increasing the incident laser power, which will cause irreparable thermal damage to the manipulated object at the same time. A femtosecond pulsed laser is used to emit linearly polarized light, which is output to a quarter-wave plate after being adjusted by a diaphragm, an attenuation plate and a first 800nm total reflection mirror, and the quarter-wave plate converts the linearly polarized light into a circle Polarized beam, the S-wave plate converts the circularly polarized beam into a cylindrical vector beam, the column vector beam is a radially polarized beam or an azimuth polarized beam, and the column vector beam enters the microscope after being adjusted by the shutter and the second 800nm total reflection mirror. The position of each component makes the optical axis of the column vector beam completely coincide with the optical axis of the imaging optical path of the microscope, and the beam is coupled into the microscope. The utility model is suitable for the field of life sciences.

Description

A control device for femtosecond laser optical tweezers based on S-wave plate

technical field

The utility model relates to an optical tweezers technology for optically manipulating particles and cells.

Background technique

Since the emergence of optical tweezers technology, optical tweezers have been widely used in life sciences, medicine, physics, materials and nanoscience due to their non-contact and non-destructive manipulation of micro-nano-scale particles, and are considered to be the most ideal single molecule , single cell, particle, micro-nano device manipulation technology.

Optical tweezers mostly use continuous laser and long pulse laser. Compared with continuous laser and long pulse laser, femtosecond laser pulse has extremely short pulse width, high peak power and time and space resolution, and can accurately detect Control action energy. At present, using a high repetition rate femtosecond laser as a light source can achieve stable capture of red blood cells, white blood cells, viruses, polystyrene microspheres, etc. At present, optical tweezers can manipulate a wide range of objects, ranging from transparent dielectric spheres, cells, to opaque materials such as metal particles, which can be directly manipulated. Gaussian beam is a traditional light source of optical tweezers. The best working area of the optical trap formed by Gaussian beam focusing is near the beam focus. In recent years, many scholars have been exploring the use of various laser light sources and designing different optical paths to realize Optical manipulation of various particles and cells, but most technologies are limited to the capture and directional movement of particles, which limits the scope of application. At the same time, the traditional optical tweezers technology improves the capture force of optical tweezers by increasing the incident laser power. While the capture power is improved, it will cause irreparable thermal damage to the manipulated object.

Utility model content

In order to solve the problem that the traditional optical tweezers technology improves the capturing force of the optical tweezers by increasing the incident laser power, while the capturing force is increased, it will cause irreparable thermal damage to the manipulated object, and proposes an S-wave-based On-chip femtosecond laser optical tweezers manipulation device.

A femtosecond laser optical tweezers control device based on an S wave plate includes a femtosecond pulse laser, an aperture, an attenuation plate, a first 800nm total reflection mirror, a quarter wave plate, an S wave plate, a shutter, a second 800nm full reflector mirrors, microscopes and stages,

The linearly polarized light emitted by the femtosecond pulse laser enters the attenuation plate through the diaphragm, and the attenuation plate attenuates the light intensity of the linearly polarized light, and then enters the linearly polarized light into the first 800nm total reflection mirror, and the first 800nm total reflection mirror The light is totally reflected to the quarter-wave plate, the quarter-wave plate converts linearly polarized light into circularly polarized light and outputs it to the S-wave plate, and the S-wave plate converts circularly polarized light into radially polarized light or azimuthal polarization Light, radially polarized light or azimuth polarized light enters the second 800nm total reflection mirror through the shutter, and the second 800nm total reflection mirror totally reflects the radially polarized light or azimuth polarized light to the objective lens of the microscope and enters the stage superior.

An S-wave plate-based femtosecond laser optical tweezers manipulation device also includes a CCD detector, which is used to convert the optical image of the light beam between the second 800nm total reflection mirror and the microscope into a digital signal and display it.

Beneficial effects: the device described in the utility model converts the linearly polarized light emitted by the femtosecond pulse laser into a radially polarized beam and an azimuthally polarized beam as captured light through a quarter-wave plate and an S-wave plate, and the cylindrical vector beam has Unique polarization mode and light intensity distribution, the captured light has a higher axial capture ability than the Gaussian beam. Compared with the use of Gaussian beam optical tweezers, the use of the cylindrical vector beam can achieve the same level as Gaussian with a small adjustment of the incident laser power. The same axial capture force of the beam, choose the cylindrical vector beam as the capture light, the incident laser power is smaller than the Gaussian beam can achieve the same axial capture force as the Gaussian beam, which can better avoid thermal damage to the manipulated object. The uneven distribution of the optical field of the cylindrical vector beam usually carries orbital angular momentum. Compared with the ordinary Gaussian laser optical tweezers technology, the beam with orbital angular momentum can stably capture and rotate the absorbing particles such as copper oxide and ferric oxide. It is possible to integrate the operation of micro-nano devices such as micro-mechanical motors. The focusing annular hollow characteristic of the azimuthal polarized beam is easy to realize high-precision, non-contact and non-damaging manipulation, so it is especially suitable for research in the field of life sciences.

The utility model uses the femtosecond laser as the light source of the optical tweezers device, and because the femtosecond laser has high time and space resolution characteristics, it provides a guarantee for improving the capturing power of the optical tweezers. Combining femtosecond laser technology with time-resolved spectroscopy technology, it can also conduct research on ultrafast biological processes in organisms and two-photon fluorescence dynamics. The high time and space resolution characteristics of femtosecond laser can also realize non-invasive local modification of cells.

Description of drawings

Fig. 1 is a schematic structural diagram of a femtosecond laser optical tweezers manipulation device based on an S-wave plate.

Detailed ways

Specific embodiments 1. This specific embodiment is described in conjunction with FIG. 1. A femtosecond laser optical tweezers control device based on an S-wave plate described in this specific embodiment includes a femtosecond pulsed laser 1, an aperture 2, an attenuation plate 3, The first 800nm total reflection mirror 4, the quarter wave plate 5, the S wave plate 6, the shutter 7, the second 800nm total reflection mirror 9, the microscope 10 and the stage 11,

The linearly polarized light emitted by the femtosecond pulse laser 1 enters the attenuation plate 3 through the aperture 2, and the attenuation plate 3 attenuates the light intensity of the linearly polarized light and then enters the linearly polarized light into the first 800nm total reflection mirror 4, and the first 800nm total reflection mirror 4 The mirror 4 totally reflects the linearly polarized light to the quarter-wave plate 5, the quarter-wave plate 5 converts the linearly polarized light into circularly polarized light and outputs it to the S-wave plate 6, and the S-wave plate 6 converts the circularly polarized light Converted to radially polarized light or azimuth polarized light, the radially polarized light or azimuth polarized light enters the second 800nm total reflection mirror 9 through the shutter 7, and the second 800nm total reflection mirror 9 polarizes the radially polarized light or azimuth angle polarization The light is totally reflected by the objective lens of the microscope 10 and is incident on the stage 11 .

In this embodiment, the femtosecond pulsed laser 1 is used to emit linearly polarized light, and the linearly polarized light is output to the quarter-wave plate 5 after being adjusted by the diaphragm 2, the attenuation plate 3 and the first 800nm total reflection mirror 4, and the quarter-wave plate 5 A wave plate 5 converts the linearly polarized light into a circularly polarized beam, and the S wave plate 6 converts the circularly polarized beam into a cylindrical vector beam, which is a radially polarized beam or an azimuthally polarized beam, and the column vector beam passes through the shutter 7 and The second 800nm total reflection mirror 9 enters the microscope 10 after adjustment, adjusts the position of each component so that the optical axis of the column vector beam coincides completely with the optical axis of the imaging optical path of the microscope 10, and couples the beam into the microscope 10.

In the microscope 10, the light beam and the imaging optical path of the microscope 10 travel in reverse, and are focused by the objective lens of the high-magnification microscope 10 to converge into a spot with a radius of less than 1 micron, forming an optical potential well, and moving the target particles on the stage 11 into the optical potential In the trap, the stable capture and rotation manipulation of target particles are realized.

The quarter-wave plate 5 described in this embodiment is used to convert linearly polarized light into left-handed circularly polarized light or right-handed circularly polarized light.

The S-wave plate 6 described in this embodiment is a new type of superstructure wave plate developed in Lithuania, which is used to convert the left-handed circularly polarized light or right-handed circularly polarized light output by the quarter-wave plate 5 into radially polarized light. Positive or azimuthally polarized light.

In this embodiment, the femtosecond laser is used as the light source of the optical tweezers device. Since the femtosecond laser has high time and space resolution characteristics, it provides a guarantee for improving the capturing force of the optical tweezers. Combining femtosecond laser technology with time-resolved spectroscopy technology, it can also conduct research on ultrafast biological processes in organisms and two-photon fluorescence dynamics. The high time and space resolution characteristics of femtosecond laser can also realize non-invasive local modification of cells.

Embodiment 2. The difference between this embodiment and the S-wave plate-based femtosecond laser optical tweezers control device described in Embodiment 1 is that the femtosecond pulsed laser 1 is a titanium-doped sapphire femtosecond laser, The output pulse repetition frequency is 76 MHz and the pulse width is 120 femtoseconds.

Embodiment 3. The difference between this embodiment and the S-wave plate-based femtosecond laser optical tweezers control device described in Embodiment 1 is that the stage 11 is a three-dimensional micro-displacement platform.

The control accuracy of the three-dimensional linear excitation source of the stage 13 in this embodiment is 50 nm.

Embodiment 4. This embodiment is described in conjunction with FIG. 1. The difference between this embodiment and the S-wave plate-based femtosecond laser optical tweezers control device described in Embodiment 1 is that it also includes a CCD detector. 8. The CCD detector 8 is used to convert the optical image of the light beam between the second 800nm total reflection mirror 9 and the microscope 10 into a digital signal and display it.

In this embodiment, a CCD detector 8 is added to monitor the converging light beams in real time, so as to know the converging conditions of the light beams.

Embodiment 5. The difference between this embodiment and the S-wave plate-based femtosecond laser optical tweezers control device described in Embodiment 1 is that it also includes an illumination circuit, and the illumination circuit includes a power supply 16, a switch 17 and the lighting lamp 15, the power supply 16, the switch 17 and the lighting lamp 15 are connected in turn to form a circuit, and the lighting lamp 15 is located directly below the stage 11.

In this embodiment, an illumination circuit is added, and when the technician observes the target particle on the stage 11 through the eyepiece, the light on the stage 11 is brighter, so that the observation result is more reliable.

Claims (5)

1. the femtosecond laser light tweezer actuation means based on S wave plate, it is characterized in that, it comprises femtosecond pulse laser (1), diaphragm (2), attenuator (3), a 800nm completely reflecting mirror (4), quarter-wave plate (5), S wave plate (6), shutter (7), the 2nd 800nm completely reflecting mirror (9), microscope (10) and objective table (11)

The linearly polarized light of femtosecond pulse laser (1) transmitting is incident to attenuator (3) through diaphragm (2), attenuator (3) carries out, after light intensity attenuation, linearly polarized light is incident to a 800nm completely reflecting mirror (4) to linearly polarized light, the one 800nm completely reflecting mirror (4) by linearly polarized light total reflection to quarter-wave plate (5), quarter-wave plate (5) is converted to circularly polarized light by linearly polarized light and exports S wave plate (6) to, circularly polarized light is converted to radial polarisation light or position angle polarized light by S wave plate (6), radial polarisation light or position angle polarized light are incident to the 2nd 800nm completely reflecting mirror (9) through shutter (7), the 2nd 800nm completely reflecting mirror (9) by radial polarisation light or position angle polarized light total reflection to the object lens of microscope (10) and be incident on objective table (11).

2. a kind of femtosecond laser light tweezer actuation means based on S wave plate according to claim 1, it is characterized in that, described femtosecond pulse laser (1) is titanium-doped sapphire femto-second laser, and output pulse repetition rate is 76 megahertzes, and pulse width is 120 femtoseconds.

3. a kind of femtosecond laser light tweezer actuation means based on S wave plate according to claim 1, is characterized in that, described objective table (11) is three-dimensional micro-displacement platform.

4. a kind of femtosecond laser light tweezer actuation means based on S wave plate according to claim 1, it is characterized in that, it also comprises ccd detector (8), and described ccd detector (8) is for being converted to the optical image of the light beam between the 2nd 800nm completely reflecting mirror (9) and microscope (10) digital signal and showing.

5. a kind of femtosecond laser light tweezer actuation means based on S wave plate according to claim 1, it is characterized in that, it also comprises lighting circuit, described lighting circuit comprises power supply (16), switch (17) and illuminating lamp (15), power supply (16), switch (17) and illuminating lamp (15) connect and compose loop successively, illuminating lamp (15) be positioned at objective table (11) under.