NL2025401B1 - Sensing device and sensing method - Google Patents

Sensing device and sensing method Download PDF

Info

Publication number
NL2025401B1
NL2025401B1 NL2025401A NL2025401A NL2025401B1 NL 2025401 B1 NL2025401 B1 NL 2025401B1 NL 2025401 A NL2025401 A NL 2025401A NL 2025401 A NL2025401 A NL 2025401A NL 2025401 B1 NL2025401 B1 NL 2025401B1
Authority
NL
Netherlands
Prior art keywords
optical element
microfluidic channel
light
sensor device
cavity
Prior art date
Application number
NL2025401A
Other languages
Dutch (nl)
Inventor
Krishna Ghatkesar Murali
Alexander Norte Richard
Original Assignee
Univ Delft Tech
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Univ Delft Tech filed Critical Univ Delft Tech
Priority to NL2025401A priority Critical patent/NL2025401B1/en
Priority to PCT/NL2021/050266 priority patent/WO2021215925A1/en
Application granted granted Critical
Publication of NL2025401B1 publication Critical patent/NL2025401B1/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N15/1023Microstructural devices for non-optical measurement
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01HMEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N9/00Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
    • G01N9/002Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N9/00Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
    • G01N9/002Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis
    • G01N2009/006Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis vibrating tube, tuning fork
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N2015/1021Measuring mass of individual particles
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10Investigating individual particles
    • G01N2015/1024Counting particles by non-optical means

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Dispersion Chemistry (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Micromachines (AREA)

Abstract

The present disclosure relates to a method and apparatus for sensing of particles suspended in a fluid which flows through a channel, characterized in that a first optical element is attached to said channel; a second optical element is arranged near said first optical element; said first optical element and said second optical element have a photonic crystal structure; an optomechanical cavity is formed in the space between said first optical element and said second optical element; light is present in said optomechanical cavity; and said particles are sensed by reading out the optomechanical resonance of said light. 15 [fig 2]

Description

SENSING DEVICE AND SENSING METHOD The present disclosure relates to a device and method for sensing a property of a fluid in a vibratile microfluidic channel.
In chemical, environmental, biological, and medical research, as well as in industrial applications, it is desirable to be able to sense the presence of particles in fluids. Microfluidics is the discipline in which microscopic scale installations are used to sense the flow of particles through small channels. As examples, the mass, density, viscosity, flow rate, or mere presence of particles could be measured.
An important limiting factor in the measurement of particles in microfluidics is the precision of the measurement instrument.
One known method of measuring in microfluidics involves running a channel over a microscopic scale cantilever; making a fluid which contains particles flow through the channel: shining a laser on the cantilever; capturing the reflection of the laser light; and from this reflection deducing a change in a resonance of the cantilever which may happen in response to the passage of particles in the fluid.
A disadvantage of the abovementioned known method is that the initial alignment of the laser system with the channel system is difficult and time-consuming. Another disadvantage is that the precision of the measurements is limited by the medium through which the laser light passes.
The method and apparatus described below provide improved sensing in order to at least partially address the abovementioned, and potentially other, problems.
According to a first aspect a method of sensing a property of a fluid in a vibratile microfluidic channel, wherein the fluid may comprise at least one particle and wherein the microfluidic channel is configured to cause the fluid to influence the vibration of the microfluidic channel, the method comprising: - providing a first optical element arranged at or close to the vibratile microfluidic channel and a second optical element arranged near the first optical element, wherein an optomechanical cavity is formed between the first optical element and the second optical element and wherein vibration of the microfluidic channel causes a change in distance between the first optical element and second optical element; - providing light into the optomechanical cavity, the changing distance between the first element and the second element forming the optomechanical cavity providing a changing mechanical resonance frequency associated with the vibration of the microfluidic channel; - leaking light from the optomechanical cavity to the second optical element: - sensing the property of the fluid from a change of mechanical resonance frequency determined from the light leaked into the second optical element.
The property of the fluid may be at least one of the mass, density, viscosity and/or flow rate of the fluid, or (more specifically) at least one of the mass, density, viscosity, flow rate and/or presence of the at least one particle in the fluid.
The method may comprise: arranging a fluid containing at least one particle in the movable microfluidic channel, the at least one particle causing motion of the microfluidic channel and the first optical element fixedly connected to or integrally formed with the microfluidic channel, wherein the motion is changed relative to motion of the fluid channel without the presence of the at least one particle; providing light in the optomechanical cavity ; leaking light from the optomechanical cavity to the second optical element; sensing the at least one particle from a change of mechanical resonance frequency determined from the light leaked into the second optical element.
The method may comprise: guiding light originating from a light source towards the second optical element; allowing light in the second optical element to be leaked into the optomechanical cavity, light in the optomechanical cavity to reflect between the first and second optical element and allowing the reflected light to leak back into the second optical element; guiding light leaked back from the second optical element towards a photo detector and detecting light received by the photo detector; determining from the light detected in the photo detector a change of the mechanical resonance frequency representative of the property of the fluid in the microfluidic channel, for instance the presence of the at least one particle in the microfluidic channel.
The types of said particles may include at least one of inorganic compounds, organic compounds, biomolecules, tissue samples, single proteins, viruses, cells, or micro-organisms.
The sensing may be performed with a precision in the order of magnitude of 10 attogram, preferably a precision in the order of magnitude of one attogram or less.
The method may involve the use of laser light. Leaking of light into and/or from the optomechanical cavity may be accomplished through evanescent coupling. The method may be performed in an environment in a vacuum or at atmospheric pressure, wherein the vacuum has a pressure down to 10° to 107" mbar. In embodiments of the present disclosure the sensing device is arranged in a gas (for instance — but not limited to — air). The gas may be at atmospheric pressure or at low pressure (or even high vacuum or ultra high vacuum, for instance at pressures below 100 nanopascal) so that the gas does not dampen the motion of the channel or less so, thereby allowing an increased sensitivity of the sensor device. Preferably the sensing device is not submerged in liquid because the mechanical sensitivity of the sensing device may be damped by the liquid.
However, a sensing device may be submerged in a liquid in case of any specific applications, for instance if the particles are larger than the channel size.
Sensing of the optomechanical resonance may comprise sensing at least one shift in at least one peak of said optomechanical resonance, wherein the frequency of the mechanical resonance is preferably between 1 kilohertz and 10 gigahertz.
The microfluidic may be brought into motion by the presence of the particle itself. In other embodiment the method comprises actively bringing the microfluidic channel and the first optical device into a background resonance state prior to sensing, for instance by making use of an actuator connected to the microfluidic channel and/or the first optical element.
According to another aspect a sensor device for sensing a property of a fluid in a vibratile microfluidic channel , wherein the fluid may comprise at least one particle, the sensor device comprising: a vibratile microfluidic channel configured to allow a fluid inside the microfluidic channel to influence the vibration of the microfluidic channel; a first optical element arranged at or close to the vibratile microfluidic channel; a second optical element arranged near the first optical element, the first and second optical elements being spaced apart to form between them an optomechanical cavity: wherein the optomechanical cavity defines a mechanical resonance frequency associated with the vibration of the microfluidic channel; wherein the second optical element is configured to allow light present in the optomechanical cavity to leak into the second optical element; a sensing unit configured to sense the at least one particle from a change of mechanical resonance frequency determined from the light leaked into the second optical element.
In embodiments of the present disclosure the first optical element is fixedly connected to or mtegrally formed with the movable microfluidic channel.
According to an embodiment the sensing unit is configured to sense from the light leaked into the second optical element a change of the mechanical resonance frequency representative of the change of the motion of the microfluidic channel resulting from the property of the fluid and/the at least one particle in the microfluidic channel.
According to an embodiment the sensor device comprises: a support; a microfluidic channel configured to allow to contain a fluid wherein at least one particle is present, wherein the microfluidic channel is arranged to be movable with respect to the support; a first optical element fixedly connected to or integrally formed with the movable microfluidic channel, the first optical element configured to move along with the movement of the microfluidic channel;
a second optical element arranged near the first optical element; wherein the first optical element comprises a first mirror surface and the second optical element comprises a second mirror surface facing the first mirror surface, the first mirror surface and second mirror surface being spaced apart to form between them an optomechanical cavity, wherein the optomechanical cavity defines a mechanical resonance frequency associated with the motion of the microfluidic channel; a light source for generating light; a photo detector for detecting light: a waveguide connected to the light source and photo detector and configured to guide light originating from the light source towards the second optical element and to guide light leaked into the optomechanical cavity from the second optical element, reflected inside the optomechanical cavity and leaked back from the optomechanical cavity into the second optical element towards the photo detector; a sensing unit connected to the photo detector and configured to determine from the light detected in the photo detector a change of the mechanical resonance frequency.
According to an embodiment the second optical element comprises a first optical element part arranged near the first optical element and comprising the first mirror surface and a second optical element part arranged near the first optical element part and forming between them a further optical cavity, the first optical element part comprising a third mirror surface and the second optical element part forming a fourth mirror surface According to an embodiment the sensor device comprises an actuator in connection with the microfluidic channel and configured to impose a vibration upon the microfluidic channel. More specifically, the actuator may be able to actively bring the microfluidic device into a background resonance state prior to sensing.
According to an embodiment the first and second optical device, and optionally also at least a portion of the microfluidic channel, are implemented on a photonic crystal. Such photonic crystal comprises a periodic nanostructure enabling a waveguide configured for extremely low-loss waveguiding and/or the creation of an optomechanical cavity having highly reflective mirrors. This may assist in a cavity with small volume and a large bounce rate of the light within the volume, which in turn allows the sensing device to work at very low optical powers which is beneficial in view of energy consumption and increases sensitivity by reducing heating due to optical absorption. In general, photonic crystals are more sensitive to small movements and have higher optomechanical coupling, i.e. large measureable resonance frequency shifts even for small displacements in cavity.
According to another aspect of the present disclosure a sensing device is provided comprising an optical resonator with at least one movable part (i.e. the first optical element and/or second optical element) that changes its optical resonance. This optical resonator could be a zipper cavity where one or both of the two photonic crystal beams are moveable.
The photonic crystal may be a movable photonic crystals forming a so-called zipper photonic crystal (zipper cavity).
5 According to an embodiment the second optical element is a static optical element.
According to an embodiment the second optical element is attached to a support element, preferably the support of the first optical element, and/or wherein the movable first optical element is configured to vibrate relative to the static second optical element.
According to an embodiment first and second optical elements, optionally also a portion of the microfluidic channel, are formed on one single integrated circuit.
According to an embodiment sensing at least one particle comprises sensing at least one of the mass density, viscosity, flow rate. or presence of the at least one particle.
According to an embodiment the sensor device is configured to sense the mass of one particle with a precision in the order of magnitude of 10 attogram, preferably a precision in the order of magnitude of one attogram or less.
According to an embodiment the light source is light with a wavelength up to 2000 nm and/or light with a wavelength between 1500 nm and 1550 nm.
According to an embodiment the waveguide comprises a first waveguide arranged to carry light from the light source to the second optical element and a second waveguide, separate from the first wave guide and arranged to carry light from the second optical element to the photo detector. The waveguides can also be combined into a single, common waveguide.
According to an embodiment the waveguide comprises an optical fiber. In embodiments of the present disclosure the use of the optical fiber may make the alignment of the part of the sensing device (except of course the first and second optical elements) to be less critical.
According to an embodiment the second optical element is configured to allow laser light to exit the second optical element and to enter the optomechanical cavity through evanescent coupling and/or the second optical element is configured to allow laser light to exit from the optomechanical cavity to enter the second optical element through evanescent coupling.
According to an embodiment the sensor device is configured to sense the at least one particle using a Pound-Drever-Hall.
According to various embodiments the cross-section of the microfluidic channel is between 10 nm and 50 wm in size, optionally between 2 um and 3 um in size; and/or the flow rate in the microfluidic channel is in the order of magnitude of several femtoliters per second, optionally less than 5 femtoliters per second; and/or the thickness of walls of the microfluidic channel is between 5 nm and 7 um; and/or the first optical element and second optical element have a length of the order of magnitude of several um, optionally between 20 and 50 um; and/or the first optical element and second optical element both have a width between 100 nm and 1500 nm; and/or the thicknesses of the first optical element and second optical element are between 20 nm and 2 um; and/or the thickness of said first optical element and said second optical element is about 300 nm: and/or the optomechanical cavity is between 10 nm and 100 pm long and/or between 100 and 300 nm wide.
According to an embodiment the sensor device is configured to sense at least one particle in an environment at a temperature between 0 and 100 degrees Celsius depending on the freezing and boiling points of the liquid in the microchannel.
According to an embodiment the sensor device is configured to sense the at least one particle in an environment at atmospheric pressure or at lower. for instance down to 10°!" mbar.
According to an embodiment the sensing unit may be configured to determine at least one shift in at least one peak of said optomechanical resonance and/or wherein the frequency of the mechanical resonance is between 1 kilohertz and 10 gigahertz.
According to an embodiment the first optical element and second optical element are made of material having relatively low optical absorption and/or wherein made of a high- tensile material, optionally a tensile strength between15 MPa and 10 GPa.
According to an embodiment the first optical element and second optical element are made partially or essentially fully of at least one of dielectric material such as silicon nitride (Si3N4), silicon carbide, or glass.
According to certain embodiments the first optical element and second optical element are made at least partially of at least one of ¢-Si, a-Si, Ges, GeSe, MoS2, SnS, MoSe2, GaAs, or diamond.
According to a further aspect an assembly is provided comprising a sensing device as defined herein and a vacuum chamber, wherein at least the movable part of the microfluidic channel, the movable first optical element and the second optical element are arranged in the vacuum chamber.
In the following description according to several figures several example of the method and sensing device will be described which may be used to sense various particles and properties thereof, the types of particles including at least one of inorganic compounds, organic compounds, biomolecules, tissue samples, single proteins, viruses, cells, or micro-organisms.
Using the method described below, and using a construction material with the appropriate properties, sensing may be performed with a precision down to attogram scale.
The method described below may be executed in an environment that is between 0 and 100 degrees Celsius. For instance. the method may be executed at room temperature, more specifically between 18 and 25 degrees Celsius. Alternatively the method may be executed at body temperature, more specifically between 35 and 40 degrees Celsius. In these cases temperature control may not be required to execute the method. Execution at room temperature or at body temperature may be advantageous when working with biological matter, which in many cases may not tolerate deviations in temperature. Alternatively the method may be executed at much lower temperatures, and/or the temperature of the environment in which the method is used may be controlled.
Examples of the method and sensing device apparatus will be described in detail by reference to the accompanying figures.
Figure 1 illustrates a first embodiment of a portion of a fluid channel coupled to an optical cavity.
Figure 2 illustrates another embodiment of a portion of a fluid channel coupled to an optical cavity.
Figures 3-6 show further embodiments of a portion of the sensing device.
Figure 7 illustrates an embodiment of the sensing device in a Pound-Drever-Hall measurement arrangement.
It is noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope of the present invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.
General outline The present disclosure relates to a method and sensing device for sensing the presence or absence of a specific specimen of an extremely small particle, for instance a virus, protein or similar particles, in a fluid present in a microfluidic channel. The particle may be a particle moving through the channel or may be (quasi) stationary during the sensing interval. The particle is somehow present in the fluid(s), for instance may form a suspension or emulsion, may be mixed with or solved in the fluid, etc. The method and device are able to sense at least one of the mass, density. viscosity, flow rate, or presence of the at least one particle (i.e. one particle or a set of particles).
The sensing device and method make use of an optomechanical cavity arranged between a first mirror surface formed by a movable first optical element and a second mirror surface formed by a static second optical element. It is to be noted here that the term "mirror surface" used throughout the present specification refers to the property of light reflectivity of the specific side of the optical element. The term is generally intended to refer to the properties of the optical element itself rather than to specific mirror like layers or similar structures provided at the side of the optical element. The reflectivity can be accomplished in various ways, for instance by the selecting an appropriate material and composition of the optical element, as will be appreciated by the person skilled in the art of optics.
The static second optical element may be attached to a support structure and is kept stationary. The microfluidic channel and the first optical element attached thereto or formed therewith may be connected to the same or to a different support structure in such a manner (for instance, the microfluidic channel may be suspended from the support structure, for instance forming a cantilever structure) that the microfluidic channel and first optical element are movable with respect to its support structure (and to the second optical element).
In some embodiments the mirror surfaces are essentially flat surfaces aligned relative to each other, i.e. the first mirror surface is arranged to extend generally parallel to the second mirror surface. In other embodiments the optical elements may have curved mirror surfaces, for instance concentric (spherical) mirror surfaces, confocal mirror surfaces, hemispherical mirror surfaces or concave-convex mirror surface.
Light from a light source coupled to the second optical element travels towards the second optical element and may partially leak into the optomechanical cavity. The light leaked into the optical cavity is reflected inside the optical cavity. A part of the reflected light may leak back into the second optical element. This part of the light leaked back into the second optical element travels in opposite direction from the second optical element and 1s detected by a light sensor, herein also referred to as a photo detector.
The optical elements on both sides of the optical cavity are arranged to allow any light entering the cavity because of leakage a light from the second optical element. to be trapped inside the cavity and reflect between the mirrors of the cavity a large number of times. The reflections produce standing waves at certain resonance frequencies.
More generally, the optomechanical cavity is used to enhance the pressure interaction between light (i.e. photons) and matter. Photons reflecting oft a mirror surface of an optical clement transfers momentum onto the mirror surface due to the conservation of momentum. The transfer of momentum may become significant since the mass of both optical elements is very small, the number of photons leaking into the cavity is relatively large (especially in cases wherein the light source is a laser light source in view of the relatively large light intensity of the laser light) and because of the arrangement of the mirror surfaces the photons in the cavity bounce off the mirror surfaces a large number of times (each time a photon hits a mirror surface momentum is transferred to the optical element). The vibrating (oscillating) first optical element causes a modulation (i.e. a variation) of the width of the optomechanical cavity, which modulation can be directly seen in the spectrum of the optomechanical cavity.
When one or more particles pass through the microfluidic channel, the mass of the one or more particles causes the microfluidic channel and therefore also the first optical device connected to the microfluidic channel or integrally formed therewith, to move. In embodiments of the present disclosure the microfluidic channel is brought into motion by an external actuator. When the microfluidic channel is brought into motion by an external actuator, a vibration may be imposed onto the movable first optical device. The presence of the one or more particles in the microfluidic channel may influence the imposed vibration. In other embodiments wherein the microfluidic channel is not brought into motion by an external actuator, the passing of the one or more particles through the microfluidic channel may itself cause the microfluidic channel and first optical element connected thereto or integrally formed therewith to be brought into a vibrating motion as well. More specifically, in both cases the mass of the one or more particles will change (i.e. shift) the mechanical resonance frequency of the movable first optical element. The change or shift of the mechanical resonance frequency of the first optical element may be measured with ultra-high precision by using the measurement arrangement comprising the optomechanical cavity formed between the movable first optical element and the second optical element.
Exemplifving embodiments Referring to figure 1 an embodiment of a portion of a sensing device 1 is depicted. The figure shows a microfluidic channel 10. The microfluidic channel is configured so that it may vibrate. The vibration can be actively generated, for instance by a motion actuator 19 provided at one end of the microfluidic channel 10, or may the result of the presence (for instance the flow) of the fluid inside the channel 10 (wherein the fluid may be a liquid, a gas or a mixture of liquid and gas, and wherein the fluid may or may not comprise one or more particles P, like biomolecules, tissue samples, single proteins, viruses, cells, micro-organisms and/or particles of inorganic compounds or organic compounds). A first optical element 2 is arranged at or close to the vibratile microfluidic channel 10, while a second optical element 3 is arranged near the first optical element. The microfluidic channel 10, first optical element 2 and second optical element may be essentially parallel to each other. An optomechanical cavity 7 is formed between the first optical element 2 and the second optical element 3. The first optical element 2 is either directly or indirectly coupled to the microfluidic channel 10 so that movement (vibration, for instance in directions P;) of the microfluidic channel 10 causes a movement of the first optical element 2 as well (directions P;, figure 1). In case of indirect coupling the first optical element 2 may be freestanding relative to the microfluidic channel 10 as is shown in figure 1. In case of direct coupling (cf. the embodiment of figure 2, for instance) the first optical element may be fixedly connected to or integrally formed with the microfluidic channel 10.
Vibration of the microchannel 10 causes variation of the distance between the first and second optical elements 2.3 and therefore variation of the width of the optomechanical cavity 7. This variation of the width of the optomechanical cavity 7 may be sensed in the following manner. Light from a light source 5 may be guided through an arbitrarily shaped waveguide 4 to an area close the second optical element 3 and therefore close to the optomechanical cavity. Light from the waveguide 4 may be leaked into the second optical element 2 (direction Ps, cf. figure 1) and light from the second optical element 3 may be leaked into the optomechanical cavity 7. Inside the optomechanical cavity 7 the light will reflect in opposite directions (Ps). causing resonance at certain frequencies. A part of the light inside the optomechanical cavity 7 will leak back into the second optical element 2 (direction Ps) and can be detected by a light detecting unit 6 connected to the waveguide 4. Changes in vibration characteristics of the microfluidic channel 10 caused by properties of the fluid (liquid and/or gas), with or without the presence of particles P, will be passed to the vibration of the first optical element 2 and therefore will result in corresponding changes in the width of the optomechanical cavity 7 and therefore in shift of the resonance frequency or frequencies (and possibly also the value of the intensity of the light at the resonance frequencies) of the light resonating inside the optomechanical cavity 7. This change of resonance frequencies can be detected by the light detecting unit 6. The light detecting unit 6 then may generate an output signal representative of the properties of the fluid or particles inside the microfluidic channel.
Referring to figure 2 another embodiment of a portion of a sensing device 1 is depicted. The figure shows a microfluidic channel 10 similar to the microfluidic channel of figure 1. The cross-section of the microfluidic channel 10, in case of a circular diameter the diameter (d. figure 1) of the microfluidic channel 10 may in the range of 10 nm to 50 um, optionally between 2 and 3 um. In the shown embodiment a first optical element 12 is integrally formed with the wall 11 of the channel 10. In other embodiments (not shown) the first optical element 12 may be a separate element that is fixedly attached to the wall 11 of the channel 10. In all these embodiments any movement of the microfluidic channel 10, like a vibration of the channel wall 11 in the transversal direction (T, cf. figure 2 wherein the figure shows the first optical element 12 (solid lines) in a left- most position, the first optical element 12 (dotted lines) in a right-most position and an imaginary center line 22 between both positions ) will be directly imparted on the first optical element 12. In other words, the first optical element co-moves with the movement of the channel wall 11.
The microfluidic channel 10 may be a freestanding channel connected to a support (not shown in the drawing), may be connected as a cantilever to the support or in a similar manner arranged in the sensing device 1. Inside the microfluidic channel a single particle (P) is traveling past the first optical element 12. The presence of the particle (P) inside the channel 10 influences the vibration characteristics of the channel 10 and the movable first element 12. In the figure an optional actuator 19 is schematically shown. The actuator 19 may be configured to bring the microfluidic channel 10 into a vibrational motion.
Spaced apart and extending generally in an axial direction parallel to the first optical element 12 a second optical element 13 is arranged. The second optical element may be a static element that has been attached to a support element, for instance the support of the first optical element or another support element . Furthermore, the first optical element 12 has a (first) mirror surface 14 facing the second optical element 13, while the second optical element 13 has a (second) mirror surface 15 facing the first optical element 12. In the shown embodiment the mirror surfaces 14 and 15 are concave mirror surfaces and the average width (W) between (the center of) both mirror surfaces 14,15 is relatively small, typically between between 100 nm and 300 nm wide. Between the mirror surfaces 14,15 an optomechanical cavity 20 is defined. Light that has leaked into this cavity 20 is reflected back and forth between the first and second optical element 12,12, as is indicated schematically by reference number 21.
Light may be present in the optical cavity 20. In some embodiments the cavity 20 is not optically shielded at the sides of the cavity which are not blocked by the optical elements 12,13 (in figure 2, the upper and lower sides of the cavity are unshielded and in fact open. However, the leakage of light from the cavity 20 is still limited.
As the particle (P) moves through the channel 10, the passage of the particle's mass may make the channel 10 vibrate (or may change the vibration the channel already has as a result of the actuator 19). This vibration may induce a mechanical resonance into the optical element 102. This mechanical resonance may affect the resonance of the light in the optical cavity 20, as is explained hereafter.
Figure 2 schematically shows a first wave guide 26 connected to a light source 28 (only shown schematically)configured to generate light and send the light through the waveguide 26 towards the second optical element 13. Light in the second optical element 13 then leaks to some extent into the optomechanical cavity 20. The light in the optomechanical cavity 20 is then caused to reflect between the (mirrors 14,15 of the) first and second optical element 12,13. A part of the light reflected between the first and second optical element 12,13 eventually is leaked back into the second optical element 13 and then transported through a second waveguide 27 to a photodetector 29 (only shown schematically). In other embodiments (shown hereafter) the first and second waveguides 26,27 have been combined into one waveguide. In any case suitable optical elements such as beam splitters may be connected to the sensing device 1 to ensure that the incoming and outgoing light is traveling in the correct directions.
Based on the light leaked back from the second optical element 13 and detected by the photo detector 29, a sensing unit 30 determines from the light detected in the photo detector 29 a change of the mechanical resonance frequency representative of the presence of the at least one particle in the microfluidic channel 10.
The embodiment shown in figure 3 is similar to the embodiment of figure 2. The second optical element 13 comprises in this embodiment a first optical element part 32 arranged near the first optical element 12 and comprising the first mirror surface 15 and a second optical element part 33 arranged near the first optical element part 33 and forming between them a further optical cavity, the first optical element part 32 comprising a third mirror surface 35 and the second optical element part forming a fourth mirror surface 36. Instead of guiding the light leaked back from the cavity 20 into the second element 13 through a waveguide 27, the light is leaking through the second cavity 31 towards the first optical clement part 33 and then (cf. 40) towards the photodetector 29 and sensing unit 30 (not shown for easy of drawing).
Figure 3 also shows a graph 41 indicating the light intensity (I) as function of frequency (w) for the situation without the presence of the particle P inside the microfluidic channel 10 (in dotted line 42) and the situation with the particle P present inside the microfluidic channel 10 (solid line 43). More specifically, the resonance peak in the sensed intensity is changed, i.e. shifted, to the right (over frequency interval 44). Due to the presence of the shift of the mechanical resonance frequency (i.¢. the resonance peaks shown in the graph) of the movable first optical element 12 and the ultra-high precision read-out de using the optical cavity / cavities, the sensing unit 30 is able to determine a change of the mechanical resonance frequency representative of the presence of the at least one particle in the microfluidic channel. The sensing unit 30 then may generate a sensing unit output signal 45 (figure 2) that is representative of the presence (or absence) of the particle in the microfluidic channel 10.
The observation that there is a shift in resonance frequency may lead to the conclusion that a particle is passing the first optical element. Furthermore. the mass of the particle can be determined from the value of the resonance frequency shift. In general, a large shift denotes a large mass while a small shift indicates a small mass.
Figure 4 illustrates an example wherein (at least) a first optical element 50 and a second optical element 51 are embodied as a photonic crystal. Figure 4 only shows the arrangement of the microfluidic channel 10, the first optical element 50 and the second optical element 51. The second optical element 51 can be connected to one or more waveguides, a light source, a photodetector and a sensing unit as is indicated in connection with figures 2 and 3. Additionally, the fluid channel may be attached at one end to a support (like a cantilever) so as to facilitate its vibration. The fluid channel and/or the attached optical first element 50 may be excited by an actuator, that is, brought into a background vibration state, or in other words a background resonance state or background resonance mode, prior to the execution of the method of sensing 10 In the embodiment of figure 4 the second element 51 is made from a material that allows light to leak out of the second optical element 51 towards the cavity 52 and from the cavity 52 towards the second optical element 51. The first and second optical elements 50,51 comprise reflecting surfaces 53,54, respectively, so as to form the optomechanical cavity 52. Furthermore, the fluid channel 10 and the optical elements 12,13,32,33,50,51may be made of a high-tensile or in other words high-strain construction material. The two optical elements may be beams. which may be constructed from a film of the construction material. The high-tensile construction material may be utilized in order to provide sufficient tensile strength to reduce noise in the mechanical resonance so as to make optimal use of the potential sensitivity of the method. A mechanical resonance of the fluid channel and/or the optical elements may vary substantially and may be between | kilohertz and 1 gigahertz, or even between 1 kilohertz and 10 gigahertz.
As mentioned above, the optical elements 50,51 may have a photonic crystal structure. The optical elements 50,51 may have a length of between 20 and 50 pm, a width of between 500 nanometers and 1500 nanometers, and a thickness of between 20 nanometers and 2 um, preferably 300 nanometers. The optical cavity 20,31,52 may be a nanocavity, that is, a cavity with nanoscale dimension. More specifically the optical cavity may have a width of between 10 nanometers and 2 um, and more preferably between 100 and 300 nanometers wide.
The optical cavity with a photonic crystal structure may more specifically be an optomechanical cavity, in which the mechanical resonance and the optical resonance are coupled to gach other to form a combined optomechanical resonance. An optomechanical resonance may have an optomechanical resonance distribution in which one or more peaks may be detected according to the presence or passage of particles in the microfluidic channel.
Figure 5 illustrates an embodiment similar to the embodiment of figure 3, wherein the fist and second optical elements 69,61 are embodied in a photonic crystal. The second optical elements 61 comprises a first optical element part 66 and a second optical element part 67. The waveguide 63 may be comprised of an optical fiber, for example. That is, the light may be shuttled to the cavity 68 between the first optical element 69 and the second optical element 61 through fiber optics. The optical element part 67 may be a beam and it may have a photonic crystal structure as well.
The optical coupling may comprise evanescent coupling, which may be described as an optical phenomenon in which some of light leaks from the third optical element into the cavity and from the cavity back to the third optical element. Evanescent coupling may be the mechanism through which light enters or is input into the optical cavity 68, and/or evanescent coupling may be the mechanism through which light exits the optical cavity.
Altematively the input/output element 63 may consist of a waveguide only, where the waveguide is an optical fiber which input, in other words shuttles, the light directly into the optical cavity, or where the waveguide takes some other form.
The light input into the optical cavity through the input/output element may be laser light, which may have a wavelength of up to 2000 nanometers, for example light in the visible spectrum, for example light with a wavelength of 500 nanometers, or for example light in the near infrared or infrared spectrum, for example light with a wavelength between 1500 and 1550 nanometers.
Figure 6 illustrates a side-view of an example of sensing device 1'. The core elements outlined above, being the channel, optical elements and/or input-output element may be constructed on the same single microchip 70. These elements may attached to the microchip throush structural elements with a specifically designed shape, or they may be attached substantially directly to the microchip.
These core elements may be manufactured out of the same piece of material in the same manufacturing process as a single integrated circuit. Manufacturing these core elements out of the same piece of material in the same process may substantially ease production and may obviate the need for an alignment step of various elements at the moment when the system is set up.
The microchip 70 may be supported by a piezoelectric element 71 which isolates the microchip and/or keeps the state of the microchip with regard to electric effects constant. The microchip and/or the piezoelectric element may be supported by a support element 72.
The fluid which may contain the particles may be input into the channel and output from the channel by microfluidic input and output elements 504 which may be attached to the microchip substantially in a plane with the core elements or which may be attached at an angle to the microchip. The angle may be such as to optimize the flow of the fluid in order to support the sensing method. The angle of the microfluidic input and output elements 73 may be adjustable.
The core elements may be present in an uncontrolled atmosphere bemg at substantially atmospheric pressure, or the core elements may be more preferably present in a controlled atmosphere, preferably substantially a vacuum. For example, a substantial vacuum could mean an environment with a pressure of down to 10°!" bar. One reason why operating in a vacuum could be preferable is to optimize the sensitivity of the method.
The light 74 input and output from the core elements is supplied by the arrangement of figure 7. The figure shows a typical Pound-Drever-Hall measurement setup. The setup comprises a laser source 81, a first beam splitter 82, a wave-meter 83. a modulator 84 for example an electro- optic modulator, a beam direction element 85 for example a second, polarizing beam splitter or a circulator, a photodetector 86, a computer 87, an oscillator 88, for example an RF oscillator, and a mixer 89. The laser source 81 may produce laser light which may pass through a first beam splitter 82 where part of the light is directed toward the wave-meter 83 in order to aid in controlling a potential error of the laser source. The laser light may pass through a phase modulator 84 or may be modulated in the laser source 81. The laser light is directed through a beam direction element 85 toward the core elements (not shown).
Returning light is directed by the beam direction element 85 toward the photodetector 86. The photodetector senses the returning light and is connected to the computer via the computer connection 87 for data acquisition.
An oscillator 88 and a mixer 89 may be used to aid in modifying the laser light, for example by impressing side bands onto the laser light. The modification of the laser light may aid in matching phases or other properties of the outwardly directed light and the retuming light, in order to aid in acquiring more precise data and/or in order to aid in controlling the laser source.
The Pound-Drever-Hall measurement setup system may measure or may enable a computer and/or software system to measure and/or display peaks in the frequency distribution of the exiting light. More specifically this measurement may comprise sensing at least one shift in at least one peak of the optomechanical resonance distribution.
Constructing the optical elements from any of the indicated materials may improve the sensing capabilities of the sensing device. Various materials are considered with various properties. being mass density, absorption coefficient and refractive index. A particularly useful material is silicon nitride (Si:Ny). The construction material may alternatively be c-S1, a-Si, Ges, GeSe, MoS,, SnS, MoSe,, GaAs, and diamond. The construction material may also alternatively be a form of glass or silicon carbide.
It may be derived that the preferred refractive index, the mass density, and the absorption of any of the materials should be in the range of 55-15, 2-7¢g em” and 0.002-1.000 cm™, respectively.
The mass density of the construction material influences its oscillation or in other words its resonance properties. The tensile strength of the construction material also influences its oscillation or in other words resonance properties. The core elements, especially the optical elements, may be made out of a high-tensile material with strength between 15 MPa and 10 GPa. A high tensile strength of the construction material will improve the sensitivity of the sensing of the core elements.
The refractive index of the construction material influences its ability to trap light.
The value of the refractive index may be optimized according to various trade-offs.
A construction material with a high refractive index will trap light more easily and will allow the cavity to contain light better and so to work better.
On the other hand, core elements made out of a construction material with a high refractive index may overheat faster.
The absorption coefficient of the construction material may also be optimized according to various trade-offs.
It is to be understood that this invention is not limited to particular aspects described, and, as such, may vary.
It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

Claims (40)

CONCLUSIES I. Werkwijze van waarnemen van een eigenschap van een fluïdum in een vibreerbaar microfluïdisch kanaal, waarbij het fluïdum ten minste één partikel kan omvatten en waarbij het microfluïdische kanaal ingericht is om het fluïdum de trilling van het microfluidisch kanaal te doen beïnvloeden, waarbij de werkwijze omvat: - het verschaffen van een eerste optisch element aangebracht op of dicht bij het vibreerbaarvibreerbare microfluïdische kanaal en een tweede optisch element opgesteld nabij het eerste optisch element, waarbij een optomechanische holte gevormd wordt tussen het eerste optisch element en het tweede optisch element en waarbij trilling van het microfluidische kanaal een verandering veroorzaakt in afstand tussen het eerste optisch element en tweede optisch element; - het verschaffen van licht naar binnen de optomechanische holte, waarbij de veranderende afstand tussen het eerste element en het tweede element die de optomechanische holte vormen een veranderende mechanische resonantiefrequentie verschaffen geassocieerd met de trilling van het microfluidische kanaal; - het lekken van licht van de optomechanische holte naar het tweede optisch element; - het waarnemen van de eigenschap van het fluïdum uit een uit het naar binnen het tweede optisch element gelekte licht bepaalde verandering van mechanische resonantiefrequentie.CONCLUSIONS I. Method of sensing a property of a fluid in a vibrable microfluidic channel, wherein the fluid may comprise at least one particle and wherein the microfluidic channel is arranged to cause the fluid to influence the vibration of the microfluidic channel, the method comprises: - providing a first optical element mounted on or close to the vibratable-vibrable microfluidic channel and a second optical element arranged near the first optical element, wherein an optomechanical cavity is formed between the first optical element and the second optical element and wherein vibration of the microfluidic channel causing a change in distance between the first optical element and second optical element; - providing light within the optomechanical cavity, the changing distance between the first element and the second element forming the optomechanical cavity providing a changing mechanical resonance frequency associated with the vibration of the microfluidic channel; - leaking light from the optomechanical cavity to the second optical element; - detecting the property of the fluid from a change of mechanical resonance frequency determined from the light leaked into the second optical element. 2. Werkwijze volgens conclusie |, waarbij het waarnemen van ten minste een eigenschap van het fluïdum ten minste één omvat van het waarnemen van de massa, dichtheid, viscositeit en/of stroomsnelheid van het fluïdum zelf.A method according to claim | wherein sensing at least one property of the fluid comprises at least one of sensing the mass, density, viscosity and/or flow rate of the fluid itself. 3. Werkwijze volgens conclusie 1 of 2, waarbij het eerste optisch element een beweegbaar optisch element is dat vast verbonden is aan of integraal gevormd met het microfluidische kanaal.The method of claim 1 or 2, wherein the first optical element is a movable optical element fixedly connected to or integrally formed with the microfluidic channel. 4, Werkwijze volgens een van de voorgaande conclusies, waarbij het tweede optisch element vrijstaand is van het eerste optisch element en/of waarbij het tweede optische element een statisch optisch element is.A method according to any one of the preceding claims, wherein the second optical element is detached from the first optical element and/or wherein the second optical element is a static optical element. 5. Werkwijze volgens een van de voorgaande conclusies, omvattend: het aanbrengen van cen ten minste één partikel bevattend fluïdum in het beweegbaar microfluidisch kanaal, waarbij het ten minste één partikel beweging veroorzaakt van het microfluidische kanaal en het eerste optische element dat vast verbonden is aan of integraal gevormd met het microfluidische kanaal, waarbij de beweging veranderd wordt ten opzichte van beweging van het floidumkanaal zonder de aanwezigheid van het ten minste één partikel; het verschaffen van licht in de optomechanische holte; het lekken van licht van de optomechanische holte naar het tweede optische element; het waarnemen van het ten minste één partikel uit een uit het naar binnen het tweede optische element gelekte licht bepaalde verandering van mechanische resonantiefrequentie.A method according to any one of the preceding claims, comprising: applying a fluid containing at least one particle to the movable microfluidic channel, wherein the at least one particle causes movement of the microfluidic channel and the first optical element rigidly connected to or formed integrally with the microfluidic channel, wherein the movement is altered relative to movement of the floidal channel without the presence of the at least one particle; providing light in the optomechanical cavity; leaking light from the optomechanical cavity to the second optical element; detecting the at least one particle from a change of mechanical resonance frequency determined from the light leaked into the second optical element. 6. Werkwijze volgens een van de voorgaande conclusies, omvattend: het geleiden van van een lichtbron afkomstig licht naar het tweede optische element; het laten lekken van licht in het tweede optische element naar binnen de optomechanische holte, het reflecteren van licht in de optomechanische holte tussen het eerste en tweede optische element en het laten teruglekken van het gereflecteerde licht naar het tweede optische element; het geleiden van terug uit het tweede optische element gelekt licht naar een fotodetector en het detecteren van door de fotodetector ontvangen licht; het uit het licht gedetecteerd in de fotodetector bepalen van een voor de eigenschap van het fluïdum in het microfluidische kanaal representatieve verandering van de mechanische resonantiefrequentie, bijvoorbeeld de aanwezigheid van het ten minste één partikel in het microfluidische kanaal.A method according to any one of the preceding claims, comprising: guiding light from a light source to the second optical element; leaking light in the second optical element into the optomechanical cavity, reflecting light in the optomechanical cavity between the first and second optical elements, and allowing the reflected light to leak back to the second optical element; guiding light leaked back from the second optical element to a photodetector and detecting light received by the photodetector; determining from the light detected in the photodetector a change of the mechanical resonance frequency representative of the property of the fluid in the microfluidic channel, for example the presence of the at least one particle in the microfluidic channel. 7. Werkwijze volgens een van de voorgaande conclusies, waarbij de soorten van die partikels ten minste één bevatten van anorganische verbindingen, organische verbindingen, biomoleculen, weefselmonsters, enkele proteïnen, virussen, cellen, of micro-organismen.A method according to any one of the preceding claims, wherein the types of said particles contain at least one of inorganic compounds, organic compounds, biomolecules, tissue samples, single proteins, viruses, cells, or microorganisms. 8. Werkwijze volgens een van de voorgaande conclusies, waarbij waarnemen uitgevoerd wordt met een precisie in de orde van grootte van 10 attogram, bij voorkeur een precisie in de orde van één attogram of minder.A method according to any one of the preceding claims, wherein sensing is performed with a precision of the order of 10 attogram, preferably a precision of the order of one attogram or less. 9. Werkwijze volgens een van de voorgaande conclusies, waarbij het licht laserlicht omvat.A method according to any one of the preceding claims, wherein the light comprises laser light. 10. Werkwijze volgens een van de voorgaande conclusies, waarbij het lekken van licht naar en/of uit de optomechanische holte volbracht wordt door evanescente koppeling.A method according to any one of the preceding claims, wherein the leakage of light into and/or out of the optomechanical cavity is accomplished by evanescent coupling. 11. Werkwijze volgens een van de voorgaande conclusies, waarbij de werkwijze uitgevoerd wordt in een omgeving in een vacuüm of onder atmosferische druk, waarbij het vacuüm een druk heeft tot zo laag als 107° mbar.A method according to any one of the preceding claims, wherein the method is performed in a vacuum or atmospheric pressure environment, the vacuum being at a pressure down to as low as 107° mbar. 12. Werkwijze volgens een van de voorgaande conclusies, waarbij dat waarnemen van die optomechanische resonantie ten minste één verschuiving van ten minste één piek van de optomechanische resonantie omvat, waarbij de frequentie van de mechanische resonantie bij voorkeur tussen 1 kilohertz en 10 gigahertz ligt.A method according to any one of the preceding claims, wherein said sensing said optomechanical resonance comprises at least one shift of at least one peak of the optomechanical resonance, wherein the frequency of the mechanical resonance is preferably between 1 kilohertz and 10 gigahertz. 13. Werkwijze volgens een van de voorgaande conclusies, die het actief in een achtergrondresonantiestaat brengen van het microfluïdische kanaal en het eerste optische element voorafgaand aan het waarnemen omvat.A method according to any one of the preceding claims, comprising actively bringing the microfluidic channel and the first optical element into a background resonance state prior to sensing. 14. Sensorinrichting voor het waarnemen van een eigenschap van een fluïdum in een vibreerbaar microfluidisch kanaal , waarbij het fluïdum ten minste één partikel kan omvatten, waarbij de sensorinrichting omvat: een vibreerbaar microfluidisch kanaal ingericht om een fluïdum binnen in het microfluidische kanaal de trilling van het microfluidische kanaal te laten beïnvloeden; een eerste optisch element aangebracht op of dicht bij het vibreerbare microfluidische kanaal; een tweede optisch element aangebracht nabij het eerste optische element, waarbij de eerste en tweede optische elementen uit elkaar geplaatst zijn om tussen hen een optomechanische holte te vormen; waarin de optomechanische holte een mechanische resonantiefreguentie definieert geassocieerd met de trilling van het microfluidische kanaal; waarbij het tweede optische element ingericht is om licht dat aanwezig is in de optomechanische holte naar binnen het tweede optische element te laten lekken; een waarneemeenheid ingericht om het ten minste één partikel waar te nemen uit een uit het naar het tweede optische element gelekte licht bepaalde verandering van mechanische resonantiefrequentie.A sensor device for sensing a property of a fluid in a vibrable microfluidic channel, the fluid may comprise at least one particle, the sensor device comprising: a vibrable microfluidic channel arranged to reduce a fluid within the microfluidic channel to the vibration of the influence the microfluidic channel; a first optical element disposed on or close to the vibrable microfluidic channel; a second optical element arranged near the first optical element, the first and second optical elements being spaced apart to form an optomechanical cavity between them; wherein the optomechanical cavity defines a mechanical resonance frequency associated with the vibration of the microfluidic channel; wherein the second optical element is configured to cause light contained in the optomechanical cavity to leak into the second optical element; a detecting unit arranged to detect the at least one particle from a change of mechanical resonance frequency determined from the light leaked to the second optical element. 15. Sensor volgens conclusie 14, waarbij het eerste optische element vast verbonden is aan of integraal gevormd met het beweegbare microfluidische kanaal.The sensor of claim 14, wherein the first optical element is rigidly connected to or integrally formed with the movable microfluidic channel. 16. Sensorinrichting volgens conclusie 14 of 15, waarbij de waarneemeenheid ingericht is om uit het naar binnen het tweede optische element gelekte licht een verandering van de mechanische resonantiefrequentie waar te nemen representatief voor de verandering van de beweging van het microfluidische kanaal resulterend uit de eigenschap van het fluïdum en/of het ten minste ene partikel in het microfluidische kanaal.A sensor device according to claim 14 or 15, wherein the detecting unit is arranged to detect from the light leaked into the second optical element a change in the mechanical resonance frequency representative of the change in the movement of the microfluidic channel resulting from the property of the fluid and/or the at least one particle in the microfluidic channel. 17. Sensorinrichting volgens een van de conclusies 14-16, die omvat: een steun; een microfluïdisch kanaal ingericht om een fluïdum te bevatten waarin ten minste één partikel aanwezig is, waarbij het microfluidische kanaal aangebracht is om beweegbaar te zijn ten opzicht van de steun; een eerste optisch element dat vast verbonden is aan of integraal gevormd met het beweegbare microfluïdische kanaal, waarbij het eerste optische element ingericht is om met de beweging van het microfluidische kanaal mee te bewegen; een tweede optisch element aanbracht nabij het eerste optische element; waarbij het eerste optische element een eerste spiegeloppervlak omvat en het tweede optische element een tweede spiegeloppervlak omvat dat gericht is naar het eerste spiegeloppervlak, waarbij het eerste spiegeloppervlak en het tweede spiegeloppervlak uit elkaar geplaatst zijn om tussen hen een optomechanische holte te vormen, waarbij de optomechanische holte een mechanische resonantiefrequentie definieert geassocieerd met de beweging van het microfluidische kanaal; een lichtbron om licht te genereren; een fotodetector om licht te detecteren; een golfgeleider die verbonden is met de lichtbron en fotodetector en ingericht om uit de lichtbron afkomstig licht te geleiden naar het tweede optische element en om uit het tweede optische element naar de optomechanische holte gelekt, in de optomechanische holte gereflecteerd en terug uit de optomechanische holte naar het tweede optische element gelekt licht te geleiden naar de fotodetector; een waarneemeenheid verbonden aan de fotodetector en ingericht om uit het in de fotodetector gedetecteerde licht een voor de eigenschappen van het fluïdum en/of het ten minste één partikel in het fluïdum representatieve verandering van de mechanische resonantiefrequentie te bepalen, bijvoorbeeld representatief voor de aanwezigheid van het ten minste één partikel in het microfluidische kanaal.A sensor device according to any one of claims 14-16, comprising: a support; a microfluidic channel configured to contain a fluid in which at least one particle is present, the microfluidic channel being arranged to be movable relative to the support; a first optical element rigidly connected to or integrally formed with the movable microfluidic channel, the first optical element adapted to move with the movement of the microfluidic channel; a second optical element disposed near the first optical element; wherein the first optical element comprises a first mirror surface and the second optical element comprises a second mirror surface facing the first mirror surface, the first mirror surface and the second mirror surface being spaced apart to form an optomechanical cavity between them, the optomechanical cavity cavity defines a mechanical resonance frequency associated with the movement of the microfluidic channel; a light source to generate light; a photo detector to detect light; a waveguide connected to the light source and photodetector and arranged to guide light from the light source to the second optical element and to be leaked from the second optical element to the optomechanical cavity, reflected in the optomechanical cavity and back from the optomechanical cavity to the second optical element guiding leaked light to the photodetector; an sensing unit connected to the photodetector and arranged to determine from the light detected in the photodetector a change of the mechanical resonance frequency representative of the properties of the fluid and/or the at least one particle in the fluid, for example representative of the presence of the at least one particle in the microfluidic channel. 18. Sensorinrichting volgens een van de conclusies 14-17, waarbij het tweede optische element een nabij het eerste optische element aangebracht en het eerste spiegeloppervlak omvattend eerste optisch elementdeel omvat en een nabij het eerste optische elementdeel aangebracht en tussen hen nog een optische holte vormend tweede optisch elementdeel, waarbij het eerste optische elementdeel een derde spiegeloppervlak omvat en het tweede optische elementdeel een vierde spiegeloppervlak vormt.A sensor device according to any one of claims 14 to 17, wherein the second optical element comprises a first optical element part arranged close to the first optical element and comprising the first mirror surface and a second optical element part arranged close to the first optical element part and forming an optical cavity between them. optical element part, wherein the first optical element part comprises a third mirror surface and the second optical element part forms a fourth mirror surface. 19. Sensorinrichting volgens een van de conclusies 14-18, dat een actuator omvat in verbinding met het microfluidische kanaal en ingericht om een trilling op te leggen aan het microfluidische kanaal.A sensor device according to any one of claims 14-18, comprising an actuator in communication with the microfluidic channel and arranged to apply a vibration to the microfluidic channel. 20. Sensorinrichting volgens een van de conclusies 14-19, waarbij de eerste en tweede optische inrichting, en eventueel ook ten minste een deel van het microfluidische kanaal, geïmplementeerd zijn op een fotonisch kristal.A sensor device according to any one of claims 14-19, wherein the first and second optical devices, and optionally also at least a part of the microfluidic channel, are implemented on a photonic crystal. 21. Sensorinrichting volgens een van de conclusies 14-20, waarbij het tweede optische element een statisch optisch element is.A sensor device according to any one of claims 14-20, wherein the second optical element is a static optical element. 22. Sensorinrichting volgens een van de conclusies 14-21, waarbij het tweede optische clement verbonden is aan een steunelement, bij voorkeur de steun van het eerste optische element, en/of waarbij het beweegbare eerste optische element ingericht is om relatief aan het statische tweede optische element te trillen.A sensor device according to any one of claims 14-21, wherein the second optical element is connected to a support element, preferably the support of the first optical element, and/or wherein the movable first optical element is arranged to be mounted relative to the static second vibrating optical element. 23. Sensorinrichting volgens een van de conclusies 14-22, waarbij eerste en tweede optische elementen, eventueel ook een deel van het microfluidische Kanaal, gevormd zijn op een enkele geïntegreerde schakeling.A sensor device according to any one of claims 14-22, wherein first and second optical elements, optionally also a part of the microfluidic channel, are formed on a single integrated circuit. 24. Sensorinrichting volgens een van de conclusies 14-23, ingericht om de massa van een partikel waar te nemen met een precisie in de orde van grootte van 10 attogram, bij voorkeur een precisie in de orde van grootte van één attogram of minder.A sensor device according to any one of claims 14-23, arranged to detect the mass of a particle with a precision of the order of 10 attogram, preferably a precision of the order of one attogram or less. 25. Sensorinrichting volgens een van de conclusies 14-24, waarbij de lichtbron een bron is van laserlicht of een laserlichtbron voor het genereren van respectievelijk zichtbaar licht en/of laserlicht.A sensor device according to any one of claims 14-24, wherein the light source is a laser light source or a laser light source for generating visible light and/or laser light, respectively. 26. Sensorinrichting volgens een van de conclusies 14-25, waarbij de lichtbron licht is met een golflengte tot 2000 nm en/of licht met een golflengte tussen 1500 nm en 1550 nm.A sensor device according to any one of claims 14-25, wherein the light source is light with a wavelength up to 2000 nm and/or light with a wavelength between 1500 nm and 1550 nm. 27. Sensorinrichting volgens een van de conclusies 14-26, waarbij de golfgeleider een eerste golfgeleider omvat die aangebracht is om licht van de lichtbron naar het tweede optische element te dragen en een tweede golfgeleider, gescheiden van de eerste golfgeleider en aangebracht om licht van het tweede optische element naar de fotodetector te dragen.A sensor device according to any one of claims 14 to 26, wherein the waveguide comprises a first waveguide arranged to carry light from the light source to the second optical element and a second waveguide separated from the first waveguide and arranged to carry light from the second optical element. second optical element to the photodetector. 28. Sensorinrichting volgens een van de conclusies 14-27, waarbij de golfgeleider een optische vezel omvat.A sensor device according to any one of claims 14-27, wherein the waveguide comprises an optical fiber. 29. Sensorinrichting volgens een van de conclusies 14-28, waarbij het tweede optische element ingericht is om laserlicht het tweede optische element te laten verlaten en de optomechanische holte te laten binnengaan door evanescente koppeling en/of waarbij het tweede optische element ingericht is om laserlicht de optomechanische holte te laten verlaten en het tweede optische element te laten binnengaan door vluchtige koppeling.A sensor device according to any one of claims 14 to 28, wherein the second optical element is arranged to allow laser light to exit the second optical element and enter the optomechanical cavity by evanescent coupling and/or wherein the second optical element is arranged to transmit laser light exit the optomechanical cavity and enter the second optical element by fusible coupling. 30. Sensorinrichting volgens een van de conclusies 14-29, ingericht om het ten minste één partikel waar te nemen met gebruik van een Pound-Drever-Hall-eenheid.A sensor device according to any one of claims 14-29, arranged to detect the at least one particle using a Pound-Drever-Hall unit. 31. Sensorinrichting volgens een van de conclusies 14-30, waarbij: de doorsnede van het microfluidische kanaal van een formaat tussen 10 nm en 50 nm is, eventueel van een formaat tussen 2 um en 3 um; en/of de stroomsnelheid in het microfluidische kanaal in de orde van grootte van verscheidene femtoliters per seconde is, eventueel minder dan 5 femtoliter per seconde; en/of de dikte van de wanden van het microfluidische kanaal tussen 5 nm en 7 nm is; en/of het eerste optische element en tweede optische element een lengte hebben in de orde van grootte van verscheidene um, eventueel tussen 20 um en 50 um; en/of het eerste optische element en tweede optische element beide een breedte hebben tussen 500 nm en 1.500 nm; en/of de diktes van het eerste optische element en tweede optische element tussen 20 nm en 2 wm zijn; en/of de diktes van dat eerste optische element en dat tweede optische element ongeveer 300 nm is; en/of de optomechanische holte tussen 10 nm en 2 um lang en/of tussen 100 en 300 nm breed is.A sensor device according to any one of claims 14-30, wherein: the diameter of the microfluidic channel is of a size between 10 nm and 50 nm, optionally of a size between 2 µm and 3 µm; and/or the flow rate in the microfluidic channel is on the order of several femtoliters per second, optionally less than 5 femtoliters per second; and/or the thickness of the walls of the microfluidic channel is between 5 nm and 7 nm; and/or the first optical element and second optical element have a length of the order of several µm, optionally between 20 µm and 50 µm; and/or the first optical element and second optical element both have a width between 500 nm and 1,500 nm; and/or the thicknesses of the first optical element and second optical element are between 20 nm and 2 µm; and/or the thicknesses of said first optical element and said second optical element is about 300 nm; and/or the optomechanical cavity is between 10 nm and 2 µm long and/or between 100 and 300 nm wide. 32. Sensorinrichting volgens een van de conclusies 14-31, ingericht om het ten minste één partikel waar te nemen in een omgeving op een temperatuur tussen 0 en 100 graden Celsius, bij voorkeur tussen 18 en 25 graden Celsius of in een omgeving tussen 35 en 40 graden Celsius.A sensor device according to any one of claims 14-31, arranged to detect the at least one particle in an environment at a temperature between 0 and 100 degrees Celsius, preferably between 18 and 25 degrees Celsius or in an environment between 35 and 100 degrees Celsius. 40 degrees Celsius. 33. Sensorinrichting volgens een van de conclusies 14-32, ingericht om de eigenschap waar te nemen in een omgeving op atmosferische druk of lager, bij voorkeur op een hoogvacuüm- druk of lager.A sensor device according to any one of claims 14-32, arranged to sense the property in an environment at atmospheric pressure or lower, preferably at a high vacuum pressure or lower. 34. Sensorinrichting volgens een van de conclusies 14-33, waarbij de waarneemeenheid ingericht is om ten minste één verschuiving in ten minste één piek van die optomechanische resonantie te bepalen en/of waarin de frequentie van de mechanische resonantie tussen | kilohertz en 10 gigahertz is.A sensor device according to any one of claims 14 to 33, wherein the sensing unit is arranged to determine at least one shift in at least one peak of said optomechanical resonance and/or wherein the frequency of the mechanical resonance is between | kilohertz and 10 gigahertz. 35. Sensorinrichting volgens een van de conclusies 14-34, waarbij de optomechanische holte in wezen onafgeschermd is aan de zijkanten van de holte die met geblokkeerd worden door de eerste en tweede optische elementen.A sensor device according to any one of claims 14 to 34, wherein the optomechanical cavity is substantially unshielded on the sides of the cavity that are not blocked by the first and second optical elements. 36. Sensorinrichting volgens een van de conclusies 14-35, waarbij het eerste optische element en dat tweede optische element gemaakt zijn van relatief weinig optisch absorberend materiaal en/of waarin gemaakt van een materiaal met hoge treksterkte, eventueel een treksterkte van tussen 15 mpa en 10 GPa.A sensor device according to any one of claims 14-35, wherein the first optical element and said second optical element are made of relatively little optically absorbing material and/or wherein made of a material with a high tensile strength, optionally a tensile strength of between 15 mpa and 10 GPa. 37. Sensorinrichting volgens een van de conclusies 14-36, waarbij het eerste optische element en tweede optische element gedeeltelijk of in wezen geheel gemaakt zijn van ten minste één van siliciummitride (Si3N4), siliciamcarbide, of glas.The sensor device of any one of claims 14 to 36, wherein the first optical element and second optical element are made partly or substantially wholly of at least one of silicon mitride (Si3N4), silicon carbide, or glass. 38. Sensorinrichting volgens een van de conclusies 14-37, waarbij het eerste optische element en tweede optische element ten minste gedeeltelijk gemaakt zijn van ten minste één van c- Si, a-Si, Ges, GeSe, MoS2, SnS, MoSe2, GaAs, of diamant.The sensor device of any one of claims 14 to 37, wherein the first optical element and second optical element are at least partially made of at least one of c-Si, a-Si, Ges, GeSe, MoS2, SnS, MoSe2, GaAs , or diamond. 39. Sensorinrichting volgens een van de conclusies 14-38, waarbij de inrichting ingericht is om de werkwijze volgens een van de conclusies 1-13 toe te passen.A sensor device according to any one of claims 14-38, wherein the device is adapted to apply the method according to any one of claims 1-13. 40. Assemblage van een sensorinrichting volgens een van de conclusies 14-39 en een vacuümkamer, waarbij ten minste het beweegbare deel van het microfluïdische kanaal, het beweegbare eerste optische element en het tweede optische element aangebracht zijn in de vacuümkamer.An assembly of a sensor device according to any one of claims 14 to 39 and a vacuum chamber, wherein at least the movable part of the microfluidic channel, the movable first optical element and the second optical element are arranged in the vacuum chamber.
NL2025401A 2020-04-22 2020-04-22 Sensing device and sensing method NL2025401B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL2025401A NL2025401B1 (en) 2020-04-22 2020-04-22 Sensing device and sensing method
PCT/NL2021/050266 WO2021215925A1 (en) 2020-04-22 2021-04-22 Sensing device and sensing method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2025401A NL2025401B1 (en) 2020-04-22 2020-04-22 Sensing device and sensing method

Publications (1)

Publication Number Publication Date
NL2025401B1 true NL2025401B1 (en) 2021-10-28

Family

ID=70805180

Family Applications (1)

Application Number Title Priority Date Filing Date
NL2025401A NL2025401B1 (en) 2020-04-22 2020-04-22 Sensing device and sensing method

Country Status (2)

Country Link
NL (1) NL2025401B1 (en)
WO (1) WO2021215925A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20240053255A1 (en) * 2022-08-15 2024-02-15 Preddio Technologies Inc. Optical sensor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100139406A1 (en) * 2008-06-19 2010-06-10 The Government Of The Us. As Represented By The Secretary Of The Navy Micromechanical chemical sensors with multiple chemoselective resonant elements and frequency division multiplexed readout
US20140051107A1 (en) * 2006-10-11 2014-02-20 Kenneth Babcock Method and Apparatus for Measuring Particle Characteristics through Mass Detection

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140051107A1 (en) * 2006-10-11 2014-02-20 Kenneth Babcock Method and Apparatus for Measuring Particle Characteristics through Mass Detection
US20100139406A1 (en) * 2008-06-19 2010-06-10 The Government Of The Us. As Represented By The Secretary Of The Navy Micromechanical chemical sensors with multiple chemoselective resonant elements and frequency division multiplexed readout

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
FREYTAG ANNICA I ET AL: "All fiber-optic viscosity, density, and temperature measurements of liquids using a photothermally actuated cantilever", APPLIED PHYSICS B: LASERS AND OPTICS, SPRINGER INTERNATIONAL, BERLIN, DE, vol. 124, no. 11, 10 October 2018 (2018-10-10), pages 1 - 9, XP036637702, ISSN: 0946-2171, DOI: 10.1007/S00340-018-7079-6 *
YA-NAN ZHANG ET AL: "A review for optical sensors based on photonic crystal cavities", SENSORS AND ACTUATORS A: PHYSICAL, vol. 233, 28 July 2015 (2015-07-28), NL, pages 374 - 389, XP055495023, ISSN: 0924-4247, DOI: 10.1016/j.sna.2015.07.025 *

Also Published As

Publication number Publication date
WO2021215925A1 (en) 2021-10-28

Similar Documents

Publication Publication Date Title
Zhang et al. Optical bio-chemical sensors based on whispering gallery mode resonators
Crespi et al. Three-dimensional Mach-Zehnder interferometer in a microfluidic chip for spatially-resolved label-free detection
Yu et al. Whispering-gallery-mode sensors for biological and physical sensing
Zhang et al. Applications and developments of on-chip biochemical sensors based on optofluidic photonic crystal cavities
Ciminelli et al. Label-free optical resonant sensors for biochemical applications
Fan et al. Overview of novel integrated optical ring resonator bio/chemical sensors
Chen et al. Label-free biosensing using cascaded double-microring resonators integrated with microfluidic channels
CN103398974B (en) A kind of Fibre Optical Sensor, preparation method and the system of measurement
NL2025401B1 (en) Sensing device and sensing method
US7995890B2 (en) Device for light-based particle manipulation on waveguides
CN111426337A (en) Sagnac interference fluid sensing system based on side-throwing optical fiber
CZ19297A3 (en) Method of optical raster microscopy of test specimen near fields in liquids, apparatus for making such method and use thereof
EP3130913B1 (en) Measurement instrument of optical characteristics for sample flowing in passage
US7106429B2 (en) Apparatus and method for detecting change of dielectric constant
Chaitavon et al. Highly sensitive refractive index measurement with a sandwiched single-flow-channel microfluidic chip
Sohlström et al. Real-time label-free biosensing with integrated planar waveguide ring resonators
KR20120042458A (en) Ringresonator sensor including asymmetric mach-zehnder interferometer, self-reference waveguide including the same and microresonator apparatuses for sensing including the same
Testa et al. Optofluidics: a new tool for sensing
Berneschi et al. A waveguide absorption filter for fluorescence measurements
Zinoviev et al. Optical biosensor based on arrays of waveguided microcantilevers
Gaira et al. Exciting Whispering Gallery Modes in liquid microdrops using sub-micron size tapered fibers
US11073421B2 (en) Methods and apparatuses for measuring optical radiation
Taguchi et al. Micro optical viscosity sensor for in situ measurement based on a laser-induced capillary wave
Han Manufacturing and aerostatic tunability of opto-mechano-fluidic resonator and its application in viscosity sensing
Domachuk et al. Fiber-based optofluidics

Legal Events

Date Code Title Description
MM Lapsed because of non-payment of the annual fee

Effective date: 20230501