Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L1/00—Measuring force or stress, in general
  • G01L1/25—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B21/00—Microscopes
  • G02B21/32—Micromanipulators structurally combined with microscopes
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
  • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
  • G21K1/06—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diffraction, refraction or reflection, e.g. monochromators

Definitions

• the invention relates to a system and methods for measuring the optical forces acting on a microscopic sample and, more particularly, to a system and methods for determining the transverse components of the force acting on a particle trapped in an assembly of optical tweezers. .
• Indirect methods have, in general, the use of a single laser beam and require a complex mathematical modeling of both the trap (harmonic potential) and its environment (homogeneous refractive index fluid and viscosity, under conditions low Reynolds number) to determine the forces acting on these microscopic samples. In addition, these must be spherical in order for the models to be suitable.
• the second possibility is to use a "direct” method.
• the precedents of "direct” methods for measuring optical forces on trapped samples require the use of two opposing propagating laser beams. This method is detailed in US Patent No. 7,133,132 (Bustamante et al.) And in two previous articles entitled “Overstretching B-DNA: The Elastic Response of Individual Double-Stranded and Single-Stranded DNA Molecules", Science, VoI. 271, pp. 795-799 (1996) and "Optical-Trap Forcé Transducer That Operates by Direct Measurement of Light Momentum", Methods of Enzymology, VoI. 361, pp. 134-162 (2003), of S. Smith and others.
• a system that includes a light source for the generation of a single beam of light, a chamber for containing a particle in a suspension medium, an entrapment objective lens to focus the light beam on the particle in such a way that the photons of the beam of light get caught the particle through the use of high gradient forces, a single lens or lens system positioned to capture both the deflected and non-deflected photons by the particle; and a light sensor device positioned at or near the rear focal plane of the collector lens, or of an optical equivalent thereof.
• a system that includes a light source for the generation of a single beam of light, a camera for containing a particle in a suspension medium, an objective lens of high numerical aperture entrapment to focus the light beam on the particle in such a way that the photons of the light beam catch the particle by means of the use of high gradient forces, a single lens or system of collector lenses positioned to capture, in the upper hemisphere of the particle that is trapped, both the deflected and non-deflected photons by the particle, said collecting lens having a numerical aperture greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber; and a light sensor device positioned at or near the rear focal plane of the collector lens, or of an optical equivalent thereof.
• a method to measure the optical forces acting on a particle which comprises the suspension of the particle in a suspension medium within a chamber, the focusing of a single beam of light on the particle in such a way that the photons of the light beam get the particle through the use of high gradient forces, the collection of both the deflected and non-deflected photons by the particle by a single lens or system of collector lenses, by means of the control of the distance of the particle with respect to the collecting lens and by controlling the refraction of the photons leaving the chamber; and the redirection of the photons collected towards a light sensor device located in or near the back focal plane of the collecting lens, or of an optical equivalent thereof.
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or system of collector lenses that is located at or near the exit face of the suspension chamber, the numerical aperture of the collector lens being greater than or equal to the refractive index of the suspension medium intended to suspend the particle in the chamber, a light sensor device positioned at or near the rear focal plane of the collector lens, or an optical equivalent thereof, the sensor device being able, directly or indirectly, to produce measurements of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the distribution of light projected on the sensor device of light.
• the collector lens and the light sensor device are integrated in a single device.
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a camera, comprising the system a single lens or system of collector lenses that is located in or near the exit face of the suspension chamber to collect, in the upper hemisphere of the particle, both the deflected and non-deflected photons by the particle, the opening being number of the selected collector lens so that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near an optical equivalent of the rear focal plane of the Ia collecting lens, the light sensor device being able, directly or indirectly, to produce measurements of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the distribution of light projected on the light sensor device; and an auxiliary or relay lens, positioned between the collector lens and the light sensor device to create the optical equivalent of the
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or system of collector lenses that is located at or near the exit face of the suspension chamber to collect, both in the upper hemisphere of the particle, both the photons deflected and not deflected by the particle , the numerical aperture of the selected collector lens being such that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near an optical equivalent of the plane focal length of the collecting lens, the light sensing device being able, directly or indirectly, to produce measurements of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the light distribution projected on the light sensor device, an auxiliary or relay lens, positioned between the collector lens and the light sensor device to create the equivalent optical focal back plane;
• the collector lens, the relay lens, the filter and the light sensor device are integrated in a single device.
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or system of collector lenses that is located at or near the exit face of the suspension chamber to collect, both in the upper hemisphere of the particle, both the photons deflected and not deflected by the particle , the numerical aperture of the selected collector lens being such that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near an optical equivalent of the plane focal length of the collecting lens, the light sensing device being able, directly or indirectly, to produce measurements of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the light distribution projected on the light sensor device,
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or collector lens system that is located at or near the exit face of the suspension chamber to collect, both in the upper hemisphere of the particle, both the deflected and non-deflected photons by the particle , the numerical aperture of the selected collector lens being such that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near an optical equivalent of the plane focal back of the collecting lens, the light sensor device being able, directly or indirectly, to produce measures of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the light distribution projected on the light sensor device, an auxiliary or relay lens, positioned between the collector lens and the sensor device of light to create the optical equivalent of the rear focal
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or system of collector lenses that is located at or near the exit face of the suspension chamber to collect, both in the upper hemisphere of the particle, both the photons deflected and not deflected by the particle , the numerical aperture of the selected collector lens being such that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near the rear focal plane of the Ia collector lens, the light sensor device being able, directly or indirectly, to produce measurements of the optical force acting on the part cula, derived from the x and y coordinates of the center of mass of the distribution of light projected on the light sensing device; and a filter positioned between the collecting lens and the light sensor device to prevent saturation of the light sensor device.
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a camera, the system comprising a single lens or collector lens system that is located in or near the exit face of the suspension chamber to collect, in the upper hemisphere of the particle, both the deflected and non-deflected photons by the particle, the numerical aperture of the selected collector lens being so that it is greater than or equal to the index of refraction of the suspension means intended to suspend the particle in the chamber, a light sensor device positioned at or near the rear focal plane of the collecting lens, the light sensor device being able, directly or indirectly, to produce measurements of the optical force acting on the particle, derived from the x and y coordinates of the center of mass of the distribution of light projected on the light sensing device; and a mask that acting by transmission and positioned near or attached to the light sensor device, compensates for the losses caused by reflection produced in the chamber
• an adaptable system for insertion into the optical train of an optical microscope, configured to trap with a single beam of light a particle suspended in a suspension means between the input face and the output face of a chamber, the system comprising a single lens or system of collector lenses that is located at or near the exit face of the suspension chamber to collect, both in the upper hemisphere of the particle, both the photons deflected and not deflected by the particle , the numerical aperture of the selected collector lens being such that it is greater than or equal to the refractive index of the suspension means intended to suspend the particle in the chamber, a light sensing device positioned at or near the rear focal plane of the Ia collector lens, the light sensor device being able, directly or indirectly, to produce measurements of the optical force acting on the part cula, derived from the x and y coordinates of the center of mass of the light distribution projected on the light sensor device, a filter positioned between the collecting lens and the light sensor device to prevent saturation of the light sensor device; and a mask
• Figure 1 illustrates a system, in one of the embodiments of the present invention, to trap a particle and measure the optical forces acting on the entrapped particle.
• Figure 2 illustrates the obtaining of the moment structure of a coherent distribution of light in the back focal plane of a lens.
• Figures 3A and 3B are examples of converging rays of light that are refracted and reflected by the trapped sample.
• Figure 4 is a graph of the intensity of light scattered as a function of the angle by a homogeneous glass microsphere suspended in water.
• Figure 5 illustrates a light collecting system in an embodiment of the present invention.
• Figure 6 is a graph showing the percentage fraction of light captured in the upper hemisphere of a sample as a function of the position of the sample inside the suspension chamber.
• Figure 7 shows an image of the back focal plane of a microscopy condenser, immersion in oil, capturing the light of the upper hemisphere of a trapped particle, according to the principles of the present invention.
• Figure 8 shows the results of a measurement experiment in which known forces are applied on polystyrene microspheres of different diameters and refractive indices and laser powers and with different microscope objectives to create the optical trap.
• Figures 9A and 9B illustrate an embodiment of the present invention that is integrated into an optical microscope.
• Figure 10 illustrates a system / device in an adaptable embodiment for insertion into the optical train of an optical microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber.
• Figure 11 illustrates a system / device in another adaptable embodiment for insertion into the optical train of an optical microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber.
• Figure 12 illustrates a system / device in another additional embodiment adaptable for insertion into the optical train of an optical microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber.
• Figure 13 illustrates a system / device in an adaptable embodiment for insertion into the optical train of an optical microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber.
• Figure 14 illustrates a system / device in another adaptable embodiment for insertion into the optical train of an optical microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber.
• Figure 15 illustrates a system / device in another additional embodiment adaptable for insertion into the optical train of an optical microscope, which It allows the measurement of the optical forces acting on a trapped particle suspended in a medium inside a suspension chamber.
• FIG. 1 illustrates a system 100 for measuring the optical forces acting on a particle 108 according to an implementation of the present invention.
• System 100 includes a chamber 109 for suspending a particle 108 in a suspension fluid, between an inlet face 109a and an outlet face 109b of a chamber, typically made of glass.
• the entrapment of the particle 108 is achieved by focusing a beam of light 124 on the suspended particle through the use of an objective lens of entrapment 107 of high numerical aperture and typically immersion, so that the photons of the beam of light are achieved trap the particle by using high gradient forces.
• a laser source 101 creates a laser beam 120 that can be manipulated such that it forms the light beam of the trap 124.
• the laser source 101 is preferably a high power laser source having an estimated power of between a few hundred milliwatts up to several watts.
• a Faraday 102 insulator can be placed at the exit of the laser source 101 to prevent the retro-reflections from entering the laser cavity 101 again, causing power fluctuations.
• a telescope 103 consisting of an ocular lens 130 and an objective lens 132, inserted into the path of the laser beam 120 expands and recolims it.
• the focal length of the lenses 132 and 130 is selected so that a laser beam 122 is obtained whose diameter covers exactly or slightly exceeds the entrance pupil 106 of the entrapment target 107.
• a quarter wave sheet 104 can be placed between the objective of the telescope 132 and the objective lens that creates the trap 107 to obtain a beam of light 123 that has circular or substantially circular polarization.
• a beam of light entering the entrapment target 107 with circular, or substantially circular, polarization allows the target to form an optical trap with equal, or substantially equal, radial elastic constants in two perpendicular directions.
• the system 100 makes use of a single beam of light 124 to trap the particle 108 through the use of high gradient forces.
• a high numerical aperture trap 107 is used, which focuses the beam to a point of diffractional dimensions on the particle.
• the entrapment objective 107 generally includes an entrance pupil 106, a series of internal lenses 140 and an exit lens 142, which is generally in contact with the entrance face 109a of a chamber 109, through an immersion means (which not shown), such as water or immersion oil, preferably oil.
• the numerical aperture of the trapping target 107 preferably ranges between approximately 0.90 and approximately 1.40.
• the magnification of the telescope 103 preferably varies between approximately 2.5X and approximately 6X.
• the measurement of the optical forces acting on the particle 108 is achieved by collecting both the deflected and non-deflected photons by the particle using a high numerical aperture immersion lens 110, which has a numerical aperture greater than or equal to the refractive index of the suspension means intended to suspend the particle 108 in the chamber 109.
• the collecting lens 110 generally includes a front lens 150 and a series of internal lenses 152 that collide and direct the collected photons towards a light sensing device 115.
• the front lens 150 It is in contact with the outlet face 109b of the chamber 109 by means of immersion means (which is not shown) such as water or immersion oil, preferably oil.
• immersion means such as water or immersion oil, preferably oil.
• the numerical opening of The collector lens 110 preferably varies between approximately 1.32 and approximately 1.40.
• the ratio between the refractive indices of the immersion medium and the suspension medium varies between approximately 1.13 and approximately 1.2, and the diameter of the front lens 150 varies between approximately 2 millimeters and approximately 20 millimeters.
• any electromagnetic field can be thought of as a superposition of plane waves, Ae i! Go , with amplitudes A given by Equation 2.
• the moment structure of the coherent light distribution of the plane 201 that is, the radiant power at the point 203 of the focal plane directly indicates the number of photons that have moment P 1 . Since the moment structure of the light distribution becomes visible in the back focal plane of a lens, any change in this moment structure is easily detectable. This provides a direct method to evaluate the force exerted by the light beam on a particle. In fact, Newton's second law identifies the force exerted on a body with its change of net momentum per unit of time.
• FIG. 3A 1 shows a beam of converging light 301 that hits a microparticle 305 in order to catch it optically.
• the microparticle 305 appears centered with respect to the focus of the beam 301.
• the light can be refracted 302 or reflected 303, resulting in directional changes in the propagation. These changes of direction can be increased when the sample moves laterally with respect to the convergent beam of light 301, as illustrated in Figure 3B. As can be seen, a lateral displacement of the sample can cause the refracted rays 302 and the reflected ones 303 to propagate practically in any direction. As a consequence, to be able to analyze all the changes in the light beam momentum, it would be necessary to collect photons at all points of a surface surrounding the sample, that is, covering a solid angle of 4p stereoradianes.
• the light scattered in the lower hemisphere of the sample is equivalent to less than 1% of the total light intensity.
• the present invention takes advantage of this phenomenon by determining the optical forces acting on the sample, maximizing the amount of light collected within the upper hemisphere of the sample and ignoring the back-scattered light.
• the collection of light in the upper hemisphere is maximized by the use of a numerical high aperture immersion collector lens 110, as described above.
• This way of proceeding provides numerous advantages and allows a much simpler optical collection of light. It should be noted that, in particular, this method allows the systems and / or devices of the present invention to be incorporated or adapted to the optical trains of conventional optical microscopes, and to the existing optical trap systems.
• a collecting system is illustrated in accordance with an embodiment of the present invention.
• the light that after being deflected by the sample 108 propagates in the direction of the collecting lens 110 forming a large angle a (half angle e) with respect to the Optical axis will be refracted at the outlet water interface 109b in accordance with Snell's law:
• the refracted rays remain within the capture angle? of the collecting lens.
• the working distance w between the outlet face 109b of the chamber 109 and the front lens 150 of the collector lens system 110 must be controlled.
• a spacer (not shown) is placed between the outlet face 109b and the collector lens 110 to maintain the working distance at a predetermined value, so that Equation 5 is met.
• the working distance is preferably maintained below 3.0 millimeters and preferably between approximately 1.0 mm and about 3.0 millimeters, and even more preferably between about 1.5 millimeters and about 2.5 millimeters.
• the depth of the sample must preferably be between 0 and approximately 200 micrometers, preferably between 0 and approximately 100 micrometers , and even more preferably between 0 and about 50 micrometers.
• the present invention makes use of thin microfluidic chambers 109 to keep the samples 108 close to both the collector lens 110 and the objective trap lens 107.
• the thickness of the chamber 109 should preferably be between about 50 and about 200 microns.
• a water immersion objective lens 107 can be used alternatively. These lenses allow working at distances of several hundred microns without reducing quality in their optical properties, and their use would advantageously facilitate the use of thicker microfluidic chambers 109.
• a light sensing device is included in the optical path of the beam after the collecting lens 110.
• the total force acting on the trapped particle 108 can be obtained by adding the individual moment changes that have suffered all photons constituting beam 128.
• this is achieved by placing a two-dimensional position sensor (PSD) device in English Position Sensitive Device) based on the side effect, on the back focal plane 111 of the collector lens or on an optical equivalent.
• PSDs are photodetectors that respond with photocurrents proportional to both the radiant power that affects each point of an exposed resistive layer, as well as the distance between the illuminated point and reference electrodes.
• the two-dimensional PSDs allow, therefore, to measure the position of a luminous point within the exposed area, according to:
• k is a constant determined by the sensitivity and geometry of the detector and l (x, y) is the irradiance of the incident beam at the coordinate point (x, y) 203 of the sensitive area.
• l (x, y) is the irradiance of the incident beam at the coordinate point (x, y) 203 of the sensitive area.
• the light sensor device is located outside the collector lens 110 and an auxiliary or relay lens 114 is used to form the image of the rear focal plane 111 of the collector lens 110 on the sensor device of light 115.
• the diameter of the relay lens is preferably greater than or equal to the diameter of the aperture diaphragm located in the rear focal plane ( and that is not shown in Figure 1) of the collecting lens and should produce an increase preferably equal to the diameter of the light sensor device divided by the diameter of the aperture diaphragm.
• the light sensor device can be a camera or other device that is capable of generating a computerized image corresponding to the optical image of the focal plane 111 of the collector lens 110, this image being actionable to obtain optical force measurements on the particle 108.
• a neutral filter 113 can be inserted in the optical path between the collector lens 110 and the sensor device 115 in order to attenuate the light coming from the trap.
• the plane can be calibrated according to the numerical aperture forming the image of the aperture diaphragm of several microscope objectives of defined characteristics.
• a diffraction network of known period illuminated by a collimated beam of known wavelength, diffracts light at well-defined and known angles (diffraction orders), which are finally focused on single points in the rear focal plane, easily identifiable .
• These orders of Diffraction can also be used to calibrate the focal plane.
• the intensity of the collected light determined experimentally is close to 95% of the total intensity of the beam (reading without sample, equivalent to the light scattered throughout the sphere of 4p radians).
• the losses due to reflection in the gap between the outlet face 109b and the suspension means 406, which are dependent on the angle, can be reduced or eliminated with a specific anti-reflective coating for multiple angles and adjusted to the wavelength of the laser, deposited on the internal surface of the exit face 109b.
• a non-uniform mask that acts by transmission (and that is not shown in Figure 1), with a radial variation of transmittance proportional to the inverse of the reflection factors, can be located in the back focal plane of the collecting lens or in its conjugates (for example, in the PSD plane) for the same purpose, since parallel beams of light within the suspension medium are focused on single points in these planes.
• the present invention is based on first principles. Once the constant C that relates the PSD readings (in volts, for example) and the light force (in piconewtons, for example) has been determined, measurements can be carried out independently of the experimental conditions, such as temperature, refractive indexes, sample size, laser power and trap geometry, etc.
• Figure 8 shows the results of an experiment in which known forces are applied on trapped polystyrene microspheres, with different diameters and refractive indices and at laser powers and with different microscope objectives to create the optical trap.
• the external force is exerted by controlled flows of the suspension medium, created by moving at a preset speed a piezoelectric platform that supports the microcamera 109.
• Stokes' force induced on the microsphere can be calculated, given that the velocity of the fluid, its viscosity and the radius of the particle are known.
• the force acts on the particle by displacing it laterally from its resting position, to a point where the force exerted by the trap exactly counteracts the viscous force of the fluid.
• the graph shows the relationship between the PSD readings (y axis), following a method of the present invention, and the known optical force as explained (Stokes force, x axis), when making sinusoidal movements with the piezoelectric platform.
• the linear relationship and the independence of the average slope with respect to the changing experimental conditions is evident in Figure 8.
• the inverse of this slope is the calibration constant C (in pN / V) that allows the PSD readings to be converted in optical force measurements. Therefore, the experiment also establishes a method to measure the C counter.
• a first and second dichroic mirrors, 105 and 122 respectively, can be added to the system 100 to allow the optical trap to be integrated into the image train of an optical microscope, selectively reflecting the laser light of entrapment and simultaneously allowing the passage of other wavelengths.
• the dichroic mirror 112 can be integrated into the illumination train of an optical microscope while the dichroic mirror 105 can be integrated into the image train.
• a collecting lens according to the present invention that collects and decomposes the light in its constituent moments it may very well be an immersion condenser, mounted on an ordinary microscope 600.
• an optical tweezers device can be mounted simultaneously to form a complete system.
• optical tweezers equipment compatible with the main brands of research microscopes, and that use the microscope's own objectives to form the optical trap.
• Figures 9A and 9B illustrate the compatibility of the method and system of the present invention with an ordinary optical microscope 600, by easily fitting into the optical train, for example, of a Kohler illuminator.
• Figure 9A schematically shows the image train and Figure 9B the lighting train of an inverted optical microscope, similar to those used in conjunction with optical tweezers equipment.
• the light of a halogen lamp 601 is redirected by a collecting lens 602 through a field diaphragm 603 and focused on the aperture diaphragm 606 of the condensing lens 610, by the collimating lens 604. Since the aperture diaphragm 606 is located in the back focal plane of the condenser lens 610, the light is collimated as it passes through the condenser, illuminating the sample 608 and being focused again by the objective 607 on its aperture diaphragm 609, located in its plane rear focal.
• collimator 604 and condenser lenses 610 form the image of field diaphragm 603 on the plane of the sample.
• the two optical trains can be understood as a succession of conjugated planes.
• the plane of the sample 608 and the field diaphragm 603 are conjugated while in the lighting train, the halogen lamp 601, the opening diaphragm 606 of the condenser 610, and the opening diaphragm 609 of objective 607 are also conjugated.
• the conjugated planes of the lighting train and those of the image train can be understood as related by Fourier transforms, since they are alternately in back focal planes of intermediate lenses.
• the opening diaphragm of the condenser 606 forms a Fourier pair with the plane of the sample 608.
• a high numerical aperture lens 610 can be used naturally, to integrate the measuring system of the present invention in the lighting train, as shown in the Figure 9B.
• a high numerical aperture lens 610 said numerical aperture being greater than or equal to the refractive index of the medium intended to suspend the sample (a modified oil immersion condenser, for example), replaces the usual condenser, working in the reverse direction as collecting lens
• a dichroic mirror 605 can be used to redirect the light that arrives from the trap towards a light sensitive detector 612, such as a PSD, which is located in the rear focal plane of the collecting lens, or in an optical equivalent of the same.
• the light that comes from the illuminator in the opposite direction crosses the dichroic mirror 605 and bathes the sample as before.
• An auxiliary or relay lens 614 may be necessary when the rear focal plane of the lens 610 is not easily accessible (as shown in Figure 9B), forming the image of the plane on the PSD. With this implementation, the microscope remains fully functional.
• Figure 10 illustrates an adaptable system / device 700 for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or collector lens system 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115, the filter 113 and the relay lens 114 are integrated with the collector lens 702 to preferably form a single device.
• the light sensor device 115 such as a PSD or a camera, is fixed on one side of the housing 705 that contains the collector lens system. In alternative embodiments, the light sensor device 115 is fixed to the housing 705 containing the collecting lens 702, but separated a certain distance by means of a support or other suitable means. Located inside the housing 705 there is also a relay lens 114 that forms the image of the light distribution located in the rear focal plane 706 on the light sensor device 115. A dichroic mirror 112 redirects the light that comes from the trap towards the light sensor device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the filter 113 is located between the dichroic mirror 112 and the light sensing device 115 to attenuate the redirected light and prevent saturation of the sensor device
• the light sensor device 115 is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format.
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• Figure 11 illustrates a system / device 720 adaptable for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or system of collector lenses 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115, the relay lens 114 and the transmission mask 721 are integrated with the collecting lens 702 to preferably form a single device.
• the light sensor device 115 such as a PSD or a camera, is fixed on one side of the housing 705 that contains the collector lens system. In alternative embodiments, the light sensor device 115 is fixed to the housing 705 containing the collecting lens 702 but separated a certain distance by means of a support or other suitable means. Located inside the housing 705 there is also a relay lens 114 that forms the image of the light distribution located in the rear focal plane 706 on the light sensor device 115. A dichroic mirror 112 redirects the light that comes from the trap towards the light sensor device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the transmission mask 721, positioned near or preferably on the light sensor device 115, is included to compensate for the losses due to reflection that presumably will occur in Ia output face 701a of the sample suspension chamber 701.
• the light sensor device 115 is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• Figure 12 illustrates a system / device 730 adaptable for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or collector lens system 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115, the filter 113, the relay lens 114 and the transmission mask 721 are integrated with the collecting lens 702 to preferably form a single device.
• the light sensor device 115 such as a PSD or a camera, is fixed on one side of the housing 705 that contains the collector lens system. In alternative embodiments, the light sensor device 115 is fixed to the housing 705 containing the collecting lens 702 but separated a certain distance by means of a support or other suitable means. Located inside the housing 705 there is also a relay lens 114 that forms the image of the light distribution located in the rear focal plane 706 on the light sensor device 115. A dichroic mirror 112 redirects the light that comes from the trap towards the light sensor device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the filter 113 is located between the dichroic mirror 112 and the light sensing device 115 to dim the light redirected and prevent saturation of the sensor device.
• the transmission mask 721, positioned near or preferably on the light sensor device 115, is included to compensate for the losses due to reflection that presumably will occur on the outlet face 701a of the sample suspension chamber 701.
• the light sensor device 115 it is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format.
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• Figure 13 illustrates a system / device 740 adaptable for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or collector lens system 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115 and the filter 113 are integrated with the collector lens 702 to preferably form a single device, the light sensor device 115 being located at or near the rear focal plane of The collector lens 702.
• a dichroic mirror 112 redirects the light that comes from the trap towards the light sensor device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the filter 113 is located between the dichroic mirror 112 and the light sensor device 115 to attenuate the redirected light and prevent saturation of the sensor device.
• the light sensor device 115 is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format.
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• Figure 14 illustrates an adaptive system / device 750 for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or system of collector lenses 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115 and a transmission mask 721 are integrated with the collector lens 702 to preferably form a single device, the light sensor device 115 being located at or near the focal plane rear of the collecting lens 702.
• a dichroic mirror 112 redirects the light that comes from the trap towards the light sensing device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the transmission mask 721, positioned near or preferably on the light sensor device 115, is included to compensate for the losses due to reflection that presumably will occur on the outlet face 701a of the sample suspension chamber 701.
• the Light sensing device 115 is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format.
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• Figure 15 illustrates a system / device 760 adaptable for insertion into the optical train of a microscope, which allows the measurement of the optical forces acting on a trapped particle suspended in a medium within a suspension chamber 701.
• the device is configured to replace the condensing lens of the microscope.
• the device includes a collector lens system 702 that includes a front lens 703 and one or several internal lenses 704.
• the function and structure of the lens or system of collector lenses 702 is similar to the collector lens 110 discussed above with the exception that the light sensor device 115, a filter 113 and a transmission mask 721 are integrated with the collecting lens 702 to preferably form a single device, the light sensor device 115 being located at or near the rear focal plane of the collecting lens 702.
• a dichroic mirror 112 redirects the light that comes from the trap towards the light sensor device 115, simultaneously allowing the light of other wavelengths to pass towards the sample.
• the filter 113 is located between the dichroic mirror 112 and the light sensor device 115 to attenuate the redirected light and prevent saturation of the sensor device.
• the transmission mask 721, positioned near or preferably on the light sensor device 115, is included to compensate for the losses due to reflection that presumably will occur in the outlet face 701a of the chamber of sample suspension 701.
• the light sensor device 115 is preferably connectable to a computer or other device via one or more connectors or cables 708, or through a wireless transmission, to produce force measurements in a readable format.
• the collector lens 702 is designed to contact the outlet face 701a of the suspension chamber 701, through a means of immersion, such as water or oil, and is designed to have a numerical aperture greater than or equal to the refractive index of the means intended to suspend the sample within the chamber 701.
• a spacer can be detachably attached to the collecting lens 702 or structurally integrated in the housing that houses 705, with the function of maintaining The desired working distance w between the collecting lens and the outlet face 701a of the chamber 701.
• the system 100 may not include each and every one of the elements shown.
• other combinations of elements and / or components may constitute a system or device for measuring the optical forces acting on a particle, without thereby deviating from the coverage and scope of the present invention.
• the system can comprise the light source 101, the camera 109, the high numerical aperture trap lens 107, the collector lens 110 with numerical aperture greater than or equal to the refractive index of the suspension means intended for suspend the sample inside the chamber, and a light sensor device located in or near the rear focal plane of the collecting lens, or in an optical equivalent thereof.
• Components 102, 104, 105, 112, 114, 130 and 132 can be omitted from the system individually or in combination with other or other components.
• the system it is not necessary for the system to be integrated into the optical train of a microscope.
• the laser source 101 and the light sensing device can be aligned directly with the optical axes of the trapping objective 107 and the collecting lens 110, thereby obviating the need to use the dichroic 105 and 112.
• a laser source 101 can be constructed that produces a collimated beam of light and / or with circular polarization, capable of covering exactly or slightly exceeding directly the entrance pupil 106 of the entrapment target 107, without the need for one or more of the components 102, 103, 130, 132 and 104. It is contemplated which components or additional features can be added to the system 100 to improve its capabilities without thereby deviating from the spirit and scope of the present invention.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Optics & Photonics (AREA)
• Analytical Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Engineering & Computer Science (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Microscoopes, Condenser (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

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• 2009
  • 2009-05-15 ES ES200901259A patent/ES2387368B1/es not_active Revoked
• 2010
  • 2010-05-14 US US13/320,503 patent/US8637803B2/en active Active
  • 2010-05-14 ES ES10774579T patent/ES2940661T3/es active Active
  • 2010-05-14 EP EP10774579.6A patent/EP2442316B1/en active Active
  • 2010-05-14 JP JP2012510322A patent/JP5728470B2/ja active Active
  • 2010-05-14 WO PCT/ES2010/000210 patent/WO2010130852A1/es not_active Ceased

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