WO2018182535A1

WO2018182535A1 - System for optical measurements and operation method

Info

Publication number: WO2018182535A1
Application number: PCT/SG2018/050164
Authority: WO
Inventors: Dinish Unnimadhava Kurup Soudamini Amma; Renzhe Bi; Chit Yaw Fu; Malini Olivo
Original assignee: Agency For Science, Technology And Research
Priority date: 2017-03-30
Filing date: 2018-03-29
Publication date: 2018-10-04

Abstract

A system for optical measurements is provided, comprising: a probe configured to illuminate and to receive a detection light from a sample; a plurality of light sources; a plurality of detectors, optically coupled to the probe and configured to receive the detection light. In a first mode, a first light source is configured to emit a first coherent light, and a first detector is configured to detect a laser speckle signal. In a second mode, a second light source is configured to emit a second coherent light, and a second detector is configured to detect a signal different from the laser speckle signal, for example diffuse reflectance spectroscopy (DRS) or Raman. A third mode may also be provided. A method is also provided, comprising selecting the first mode and carrying out a diffuse speckle contrast analysis (DSCA) measurement of the laser speckle signal, and selecting a different mode from the first mode and carrying out a second measurement.

Description

SYSTEM FOR OPTICAL MEASUREMENTS AND OPERATION METHOD

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of Singapore application No. 10201702591V filed March 30, 2017, the contents of it being hereby incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] The present disclosure relates to a system for optical measurements of a sample. The present disclosure also relates to a method for operating a system for optical measurements.

BACKGROUND

[0003] Conventional systems for optical measurements have several limitations. For instance they only allow for a certain type of measurement. Thus enabling only the analysis of the sample according to the limitations of the respective type of measurement. Also, many conventional systems for optical measurements may be bulky and difficult to handle.

[0004] Therefore, there is a need to provide for improved systems.

SUMMARY

[0005] According to various embodiments, a system for optical measurements of a sample is provided. The system may include a probe. The probe may be configured to illuminate the sample. The probe may be further configured to receive a detection light from the sample. The system may include a plurality of light sources including at least a first light source and a second light source. The plurality of light sources may further include a third light source. The system may include a plurality of detectors, including at least a first detector and a second detector. The plurality of detectors may further include a third detector. Each of the plurality of detectors may be optically coupled to the probe. Each of the plurality of detectors may be configured to receive the detection light, for example via the probe. In a first mode of the system, the first light source may be configured to emit a first coherent light, and the first detector may be configured to detect a laser speckle signal. The laser speckle signal may be scattered by the sample and received by the probe as the detection light when the sample is illuminated with the first coherent light. In a second mode of the system, the second light source may be configured to emit a second coherent light, and the second detector may be configured to detect a signal different from the laser speckle signal. The signal different from the laser speckle signal may be scattered by the sample and received by the probe as the detection light when the sample is illuminated with the second coherent light.

[0006] According to various embodiments, a method for operating a system for optical measurements is provided. The method may include selecting the first mode and carrying out a DSCA measurement of the laser speckle signal, and selecting a different mode from the first mode and carrying out a second measurement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:

[0008] FIG. 1 shows a schematic illustration of a system 100 according to various embodiments.

[0009] FIG. 2 shows a probe 110 according to various embodiments, held by a hand 200.

[0010] FIG. 3 shows a flow chart of a method 300 according to various embodiments.

[0011] FIG. 4A shows a schematic illustration of a system 100 according to various embodiments, in a first mode.

[0012] FIG. 4B shows a schematic illustration of a system 100 according to various embodiments, in a second mode.

[0013] FIG. 4C shows a schematic illustration of a system 100 according to various embodiments, in a third mode.

[0014] The figures are of schematic nature, the proportion and scale may have been modified to improve the visibility and to easier explain the invention.

DETAILED DESCRIPTION

[0015] The following detailed description describes specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0016] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. For instance, embodiments of the system may explain details of the method which may be combined with the embodiments of the system. Also, embodiments explaining the method may be combined with embodiments of the system. Furthermore, additions and/or combinations and/or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0017] The invention illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising", "including," containing", etc. shall be read expansively and without limitation. The word "comprise" or variations such as "comprises" or "comprising" will accordingly be understood to imply the inclusion of a stated integer or groups of integers but not the exclusion of any other integer or group of integers. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

[0018] The reference signs included in parenthesis in the claims are for ease of understanding of the invention and have no limiting effect on the scope of the claims.

[0019] In the context of the present disclosure and also according to various embodiments, the articles "a", "an" and "the" as used with regard to a feature or element include a reference to one or more of the features or elements. [0020] In the context of the present disclosure and also according to various embodiments, the term "system" may refer to a fiber optics spectroscopy system.

[0021] In the context of the present disclosure and also according to various embodiments, the term "system" may be implemented as an apparatus.

[0022] According to various embodiments, a system is disclosed which allows, for example, Raman spectroscopy, diffuse speckle contrast analysis (DSCA), and diffuse reflectance spectroscopy (DRS). Thus, the system may be called a multi-functional Fiber Optical Spectroscopy System (MFOS System). The system may combine the following optical modalities: DSCA and DRS into one hand-held probe. The probe is designed in such a way to allow different kinds of measurement, for example Raman spectroscopy, DSCA and DRS, to be taken on the same location. The system may be used in biomedical applications, such as wound healing study and/or monitoring.

[0023] The probe and computation unit may be configured to make sure the three modes (Raman spectroscopy, DSCA, DRS) do not interfere with each other, so that only one light source is coupled to the probe and able to illuminate the sample at one time point. The measurements may be taken sequentially and repeatedly. The time interval between measurements may be 5 milliseconds or less.

[0024] Measurements from different modes (e.g. Raman spectroscopy, DSCA, DRS) may be processed to a combined processed result, which may carry new information. For example, DSCA may provide blood perfusion measurement of a target tissue. DRS may provide concentration of different chromophores such as oxy-hemoglobin and deoxy- hemoglobin. The DSCA and DRS measurements may be combined to provide, information of metabolism rate of the target tissue, for example using perfusion and hemoglobin concentration. To elaborate how three different modes are processed to provide one or more new information, a case of a skin disorder, such as rosacea or melasma, is referred to as an example. With DSCA, the blood flow information can be obtained, and this blood flow information may be studied to determine if the information is related, directly or indirectly, to the skin diseases. The DRS can provide information on the concentration of endogenous absorbers like hemoglobin, melanin, water, fats, etc. The concentration of hemoglobin, specifically oxygenated and de-oxygenated hemoglobin can be obtained to calculate, for example, saturation level of oxygen. The Raman mode can provide information on any molecular change happening during a process (e.g. application or consumption of a drug) or to provide fingerprints of different molecules. The processing of the Raman information may involve subtraction of background fluorescence and further dissecting the information to obtain, for example, the relative concentration of components such as collagen, ceramide, etc. In the field of wound healing care, the information can be used to decide the type of wound and the wound healing stage from the detected biomedical marker detected by, for example, Raman spectroscopy. Furthermore, by combining the information from metabolism rate and bio-marker, clinicians may be able to provide better and more accurate wound care methods and monitor the wound healing progress. The measurements from the different modes may be combined together for example, for applications such as wound healing and skin ageing. As demonstrated above, these three distinct modes can provide different information that complement each other for disease diagnosis, which in turn allows for a treatment plan to be improved. These three distinct modes, through their combined use, can also be used for treatment monitoring. The present system may be further configured to process each measurement of the DSCA measurement, the Raman measurement, and the DRS measurement together to generate one or more information according to various embodiments. Processing of all these information may be carried out with an integrated component (e.g. containing an integrated software) for such processing.

[0025] The system according to various embodiments, may include a computation unit. Alternatively or in addition, the spectroscopy system according to various embodiments may be connectable to a computation unit, such as a personal computation device (for example a personal computer). The computation unit may be configured, for example, for at least one of: controlling the system, data processing, data presentation, a combination of the foregoing.

[0026] In the context of the present disclosure and also according to various embodiments, the term "probe" may refer to a device which is able to be held by a hand, for example by a hand of an user (also called operator). The probe may be elongated and may include an optical input on a first side configured to receive the detection light. The fiber optics coupled to the probe, for example the bundle, may be connected to the probe from a side opposed to the first side. The term "connected" as used herein may refer to a mechanical connection, for example a fiber optics connector, or an opening in a casing of the probe through which hole the fiber optics, for example the bundle, may protrude from the casing. The probe of the present disclosure, which may also be called fiber-based hand-held probe, is developed for easy operation. The probe integrates the optical fibers, for example the fibers coupling the light sources to the probe and the detection optical fibers of all three modes (Raman spectroscopy, DSCA, DRS) to enable different measurements on the same sample. The probe also provides much more freedom in operation than free space optical system.

[0027] In the context of the present disclosure and also according to various embodiments, the term "light source", for example as in a plurality of light sources, may refer to a source of coherent light or a source of broad optical bandwidth light that includes the visible spectral region of the electromagnetic spectrum. An example of a broad optical bandwidth light may be a broadband white light. Each of the first light source, the second light source, and the third light sources may be configured to emit light with a peak wavelength different from each other. For example, two out of the three light sources may each include a light source that emits laser and the other (i.e. in this instance, the third light source) may be or may include a light source that emits a broadband white light that is not a laser.

[0028] In the context of the present disclosure and also according to various embodiments, the term "mode", may refer to one of the modes to which the system may be configured to carry out measurements. For example, in a first mode the first light source may be configured to emit a first coherent light, the first light source may be optically coupled to the probe, and the first detector may be configured to detect a laser speckle signal, scattered by the sample and received by the probe as the detection light when the sample is illuminated with the first coherent light. Further, in a second mode the second light source may be configured to emit a second coherent light, the second light source may be optically coupled to the probe, and the second detector may be configured to detect a signal different from the laser speckle signal (for example Raman signal), scattered by the sample and received by the probe as the detection light when the sample is illuminated with the second coherent light. Further, in a third mode, the third light source is configured to emit a third coherent light, the third light source may be optically coupled to the probe, and the third detector may be configured to detect a third signal (for example DRS signal), scattered by the sample and received by the probe as the detection light when the sample is illuminated with the third coherent light.

[0029] In some embodiments, the optical coupling of each of the plurality of light sources to the probe may be provided with respective filters and respective fibers connecting each light source to the probe. It is preferred, in various embodiments, to provide the optical coupling between each of the plurality of light sources to the probe via a switcher. In the following a switcher is used as an example of the optically coupling, however it is understood that other alternatives of optical coupling of each of the plurality of light sources to the probe are also envisaged by the present disclosure.

[0030] In the context of the present disclosure and also according to various embodiments, the expression "detection optical fiber" (in singular or plural), may refer to one of the optical fibers associated to one of the plurality of detectors, for example the first detector, the second detector, or the third detector. Similarly, the expression "each of the respective detection optical fiber" may refer to each of the detection optical fibers. For example each of the respective detection optical fiber may refer to each of a first detection optical fiber, which may optically couple the probe to the first detector, a second detection optical fiber, which may optically couple the probe to the second detector, and a third detection optical fiber, which may optically couple the probe to the third detector if a third detector is provided for.

[0031] In the context of the present disclosure and also according to various embodiments, the term "switcher", may refer to a switcher configured to optically couple one of the plurality of light sources to the probe. The switcher may be configured so that for one mode, only light from one light source of the plurality of light sources is transmitted to the probe. In one example the switcher is a fiber switch. The switcher may include a plurality of input ports and a common output port. Any, for example each, of the plurality of light sources may be optically coupled to a respective input port of the switch. The switcher may be configured to select the optical coupling between one input port of the plurality of input ports at a time and an output. Thus, for one mode, only light from one light source of the plurality of light sources is transmitted to the output, and thus to the probe. Due to the use of a switcher it is possible to rapidly and accurately switch between different light sources, with a simple control means, since only the switcher needs to be controlled, in contrast, for example, to controlling each of the light sources. The plurality of light sources may be optically coupled to a switcher configured to optically couple one of the plurality of light sources to the probe, wherein in the first mode, the first light source may be optically coupled to the probe via the switch, in the second mode, the second light source is optically coupled to the probe via the switch, according to some embodiments. The switcher may be optically coupled to the probe via an excitation optical fiber according to some embodiments.

[0032] According to various embodiments, the first light source of the plurality of light sources may be a light source for DSCA spectroscopy. DSCA spectroscopy utilizes a lower power coherent laser source instead of a higher power laser or a broadband white light (i.e. not a laser) for Raman and DRS spectroscopy, respectively.

[0033] According to various embodiments, the first detector of the plurality of detectors may be a detector for DSCA spectroscopy. The detector may be optically coupled to the probe and configured to receive the detection light from the sample, via the probe, and for example, via a respective detection optical fiber. The first detector for DSCA spectroscopy, includes a compact charge-coupled device (CCD) camera for detecting laser speckle signal. This CCD camera is distinguished from the second and third detectors in that the CCD camera specifically detects a laser speckle signal from a lower power coherent laser source instead of the higher power Raman laser or the broadband white light of a DRS light source. A laser speckle signal may be a laser that has been projected onto and scattered from a random medium to produce a random interference pattern referred to as the speckle. Meanwhile, the broadband white light in DRS is not a laser. This CCD camera also differs from the detector for Raman spectroscopy and DRS detector, which need a higher sensitivity cooled and high resolution spectrometer, and a broadband light spectrometer, respectively.

[0034] The CCD camera for DSCA is not to be mistaken as a detector for diffuse correlation spectroscopy (DCS). The difference is that the CCD camera is a single detection component for use in DSCA while the DCS involves coupled detection components, i.e. a photon detector and correlator (i.e. a hardware, or containing a software, for analyzing signals). The DCS photon detector is of a higher sensitivity than the CCD camera, and this makes the present system advantageous over DCS in that such a photon detector of higher sensitivity and correlator are circumvented.

[0035] According to various embodiments, when the first mode is selected, the first light source and the first detector cooperate and the system may be configured as a DSCA spectroscopy system.

[0036] According to various embodiments, one light source of the plurality of light sources, for example the second light source or the third light source, may be a light source for Raman spectroscopy. The light source for Raman spectroscopy may be a laser. The light source may be configured to provide light with a single emission peak, for example by filtering out unwanted parts of the spectrum, for example with a notch filter.

[0037] According to various embodiments, one detector of the plurality of detectors, for example the second detector or the third detector, may be a detector for Raman spectroscopy. The detector may be optically coupled to the probe and configured to receive the detection light from the sample, via the probe, and for example, via a respective detection optical fiber. The detector may include a sensor for detecting the light intensity resolved over the wavelength, for example with the use of a grating. The detector may include a filter for blocking part of the light from the light source, and thus only allowing the Raman signal (e.g. Stokes and/or anti-Stokes) to be transmitted.

[0038] According to various embodiments, in a mode in which the light from a light source for Raman spectroscopy is coupled to the probe (for example in the second mode), the light source for Raman spectroscopy and the detector for Raman spectroscopy cooperate and the system may be configured as a Raman spectroscopy system. For example, the second light source may be a light source for Raman spectroscopy, the second detector may be a detector for Raman spectroscopy, and in the second mode the second light source may be optically coupled to the probe via the switch. For example the sample may be illuminated with light from the Raman source, and scattered light, including Raman signal (e.g. Stokes and/or anti- Stokes), may be received as the detection light by detector via the probe. The detection data may be further processed.

[0039] According to various embodiments, one light source of the plurality of light sources, for example the second light source or the third light source, may be a light source for DRS spectroscopy. The DRS light source is or includes a broadband light source, e.g. one that emits broadband white light. The DRS broadband light source is not a laser source (i.e. does not emit laser), unlike the DSCA light source which provides, for example, a low power single wavelength laser while the Raman light source provides, for example, a higher power single wavelength laser.

[0040] According to various embodiments, one detector of the plurality of detectors, for example the second detector or the third detector, may be a detector for DRS spectroscopy. The detector may be optically coupled to the probe and configured to receive the detection light from the sample, via the probe, and for example, via a respective detection optical fiber.

[0041] According to various embodiments, in a mode in which the light from a light source for DRS spectroscopy is coupled to the probe (for example in the third mode), the light source for DRS spectroscopy and the detector for DRS spectroscopy cooperate and the system may be configured as a DRS spectroscopy system. For example the third light source may be a light source for DRS spectroscopy, the third detector may be a detector for DRS spectroscopy, and in the third mode the third light source may be optically coupled to the probe via the switch.

[0042] FIG. 1 shows a schematic illustration of a system 100 according to various embodiments. The system 100 may include a plurality of light sources, for example at least a first light source 120 and a second light source 130. The system may include a probe 110 configured to illuminate a sample and configured to receive the detection light. The system 100 may further include a third light source 140. Each light source of the plurality of light sources may be optically coupled to a switcher 150. The first light source 120 may be optically coupled to the switcher 150 via a first light source optical fiber 122. The second light source 130 may be optically coupled to the switcher 150 via a second light source optical fiber 132. The third light source 140, if present, may be optically coupled to the switcher 150 via a third light source optical fiber 142. The switcher 150 may be configured to optically couple one of the plurality of light sources and the probe 110. For example, in the first mode the first light source is coupled to the excitation optical fiber 1 12, and to the probe 110, via the switcher 150; in the second mode the second light source 130 is coupled to the excitation optical fiber 112, and to the probe 110, via the switcher 150; in the third mode the third light source 140 is coupled to the excitation optical fiber 112, and to the probe 110, via the switcher 150.

[0043] The system 100, as shown in FIG. 1 and in accordance to various embodiments, may include a plurality of detectors. Each detector of the plurality of detectors may be optically coupled to the probe via respective detector optical fibers. The system 100 may include a first detector 160 which may be optically coupled to the probe 1 10, for example via a first detection optical fiber 162. The system 100 may include a second detector 170 which may be optically coupled to the probe 110, for example via a second detection optical fiber 172. The system 100 may optionally include a third detector 180 which may be optically coupled to the probe 110, for example via a third detection optical fiber 182.

[0044] The system 100, as shown in FIG. 1 and in accordance to various embodiments, may be configured to: a) select the first mode and carry out a first measurement; and may further be configured to carry out at least one of following the steps b) or c): b) select the second mode and carry out a second measurement; c) select the third mode and carry out a third measurement. As already previously explained, the third mode presumes that a third light source and a third detector are included in the system. In an example 1, the first light source is a light source for DSCA spectroscopy, the second light source is a light source for Raman spectroscopy, the third light source is a light source for DRS spectroscopy, the first detector is a detector for DSCA spectroscopy, the second detector is a detector for Raman spectroscopy, and the third detector is a detector for DRS spectroscopy. In an example 2, the first light source is a light source for DSCA spectroscopy, the second light source is a light source for DRS spectroscopy, the third light source is a light source for Raman spectroscopy, the first detector is a detector for DSCA spectroscopy, the second detector is a detector for DRS spectroscopy, and the third detector is a detector for Raman spectroscopy.

[0045] The system 100, as shown in FIG. 1 and in accordance to various embodiments, may include a computation unit 190 operable in communication with the switcher 150 for selecting the light source of the plurality of light sources which is coupled to the probe, for example the computation unit 190 may be connected to the switcher via a communication interface 154. The switcher may also be operable in communication with the plurality of detectors for receiving a respective detection data, for example the computation unit 190 may be connected to the first detector 196 via a communication interface 164, to the second detector 170 via a communication interface 174, and to the third detector 180 via a communication interface 184. Each of the communication interfaces 154, 164, 174, 184 may be independently selected from: a wireless communication interface, a wired communication interface. The computation unit 190 may include a personal computer.

[0046] FIG. 2 shows a probe 110 according to various embodiments, held by a hand 200. The probe 110 is shown, as an example, as an elongated cylinder. The probe may include an opening 114 to receive detection light, for example light scattered by a sample facing the opening, when the sample is illuminated with light from one of the plurality of the light sources. The same opening 114 may also be configured for illuminating the sample, with light from one of the plurality of the light sources. FIG. 2 also shows a bundle extending from the probe 110 to a console 196. The bundle may include the excitation optical fiber and each of the respective detection optical fibers. The bundle may have a length of at least 1.5 meter, optionally at least 2 meters. The length of the bundle may refer to the length between the probe 110 and the console 196. The console 196 may include a casing, which may encase components such as the detectors and the light sources. Due to the use of a switcher the number of fiber optics connecting to the probe may be kept lower, the optics in the probe is simplified and less prone to mechanical failure. The probe may be easily moved, and is very practical, for example, in a clinical environment.

[0047] In accordance to various embodiments, the probe may include a scanning system, configured to illuminate a plurality of positions, for example to scan a certain area of the sample, and the system may be configured to carry out a measurement for the plurality of different positions. Thus a probe including a scanning system may be able to generate two dimensional maps (e.g. images) from the sample with the information from each respective measurement or with the combined processed result.

[0048] FIG. 3 shows a flow chart of a method 300 according to various embodiments. In a method step 310, the first mode may be selected and a DSCA measurement of the laser speckle signal may be carried out. In a method step 320, the second mode may be selected and a Raman measurement of the Raman signal may be carried out. In a method step 330, the third mode may be selected and a DRS measurement of the DRS signal may be carried out. Step 310, 320, 330 may be carried out in any order, for example, they may be carried out as shown, or, for example, step 330 may be carried out before step 320. In another example, step 320 may be followed by step 330, which in turn may be followed by step 310. In another example step 320 may be followed by step 310, which in turn may be followed by step 330. In yet another example step 330 may be followed by step 310, which in turn may be followed by step 320. In yet another example step 330 may be followed by step 320, which in turn may be followed by step 310.

[0049] After the measurements are taken in steps 310-330 as described above, each of the measurements may be processed together in a step 340, for example, a detection data of the DSCA measurement, a detection data of the Raman measurement and a detection data of the DRS measurement may be processed to a combined processed result, wherein the combined processed result may contain processed information. Steps 310-330 may be repeated more than once before step 340. In some embodiments, step 320 may be left out and no detection data of Raman signal is processed in step 340. In other embodiments, step 330 may be left out and no detection data of DRS signal is processed in step 340.

[0050] The steps as described in connection with FIG. 3 may be repeated. For example after each step 340, a combined processed result may be transformed into a format which may convey information to a user, for example in visual form. The visual format may carry information to the user about the processed results. Due to the repetition, the user may obtain a result of the sample being measured without noticeable delay. According to various embodiments, each of the steps 310-330 is carried out within a defined time period of 5 milliseconds or less. The user may concentrate on the combined processed result without requiring to concentrate on the individual (e.g. Raman, DSCA, DRS) measurements, for example. Due to the use of the switcher, it is possible to have a fast enough switching time to create a perception of an immediate response. For example, with a combined time of 15 milliseconds or less for steps 310-330, it is possible to show 6 results per second. The repetition may proceed for as long as required by the user.

[0051] FIGs. 1 A-4C is used to exemplify the functioning principles of the present disclosure in accordance to various embodiments. As an example the second set of light sources and detectors are for Raman spectroscopy and the third set are for DRS spectroscopy, as in example 1 above. However, the present disclosure also encompasses the alternate configuration, as in example 2 above.

[0052] FIG. 4A shows a schematic illustration of a system 100 according to various embodiments, in a first mode. In the first mode, the first light source 120 is optically coupled to the probe 110 via the switcher 150. In the first mode, the other light sources 130 and 140 are not ^"optically coupled to the probe 110 as the switcher 150 does not enable this coupling in the first mode. Thus, in the first mode, the first light source 120, the probe 110 and the first detector 160 are the active parts, emphasized by the dashed line 152, and the system 100 is configured to carry out first type of measurement, for example for DSCA measurements.

[0053] Switching to the second mode, schematically illustrated in FIG. 4B by the dashed line 154, the second light source 130 is optically coupled to the probe 110 via the switcher 150. In the second mode, the other light sources 120 and 140 are not optically coupled to the probe 110 as the switcher 150 does not enable this coupling in the second mode. Thus, in the second mode, the second light source 130, the probe 110 and the second detector 170 are the active parts, emphasized by the dashed line 154, and the system 100 is configured to carry out a second type of measurement, for example for Raman measurements.

[0054] Switching to the third mode, schematically illustrated in FIG. 4C by the dashed line 156, the third light source 140 is optically coupled to the probe 110 via the switcher 150. In the third mode, the other light sources 120 and 130 are not optically coupled to the probe 110 as the switcher 150 does not enable this coupling in the third mode. Thus, in the third mode, the third light source 140, the probe 1 10 and the third detector 180 are the active parts, emphasized by the dashed line 156, and the system 100 is configured to carry out a third type of measurement, for example for DRS measurements.

Claims

1. A system for optical measurements of a sample, comprising:

- a probe configured to illuminate the sample and configured to receive a detection light from the sample;

- a plurality of light sources comprising at least a first light source and a second light source;

- a plurality of detectors, comprising at least a first detector and a second detector, optically coupled to the probe and configured to receive the detection light;

- wherein the first light source is configured to emit a first coherent light, and the first detector is configured to detect a laser speckle signal, scattered by the sample and received by the probe as the detection light when the sample is illuminated with the first coherent light, in a first mode; and

wherein the second light source is configured to emit a second coherent light, and the second detector is configured to detect a signal different from the laser speckle signal, scattered by the sample and received by the probe as the detection light when the sample is illuminated with the second coherent light, in a second mode.

2. The system of claim 1, wherein the plurality of light sources are optically coupled to a switcher configured to optically couple one of the plurality of light sources to the probe;

wherein in the first mode, the first light source is optically coupled to the probe via the switch; in the second mode, the second light source is optically coupled to the probe via the switch.

3. The system of claim 2, wherein, the switcher is optically coupled to the probe via an excitation optical fiber.

4. The system of claim 3, wherein in the second mode, the signal different from the laser speckle signal is a Raman signal.

5. The system of any one of the previous claims, wherein the plurality of light sources further comprises a third light source.

6. The system of any one of the previous claims, wherein the plurality of detectors further comprises a third detector.

7. The system of any one of the previous claims, wherein in a third mode, the third light source is optically coupled to the probe via the switch;

wherein the third light source is configured to emit a third coherent light, and the third detector is configured to detect a DRS signal, scattered by the sample and received by the probe as the detection light when the sample is illuminated with the third coherent light, in the third mode.

8. The system of any one of the previous claims, wherein each of the plurality of detectors is optically coupled to the probe via a respective detection optical fiber.

9. The system of claim 8 as far as dependent on claim 2, further comprising a console, wherein the excitation optical fiber and each of the respective detection optical fiber are comprised in a bundle which extends at least from the console to the probe.

10. The system of claim 9, wherein the bundle has a length of at least 1.5 meter, optionally at least 2 meters.

11. The system of any one of the previous claims, further comprising a computation unit operable in communication with the switcher for selecting which light source of the plurality of light sources is coupled with the probe, and further operable in communication with the plurality of detectors for receiving a respective detection data.

12. The system of any one of the previous claims, further configured to:

a) select the first mode and carry out a DSCA measurement of the laser speckle signal; and further configured to carry out at least one of the steps b) or c) below:

b) select the second mode of claim 4 and carry out a Raman measurement of the Raman signal;

c) select the third mode of claim 7 and carry out a DRS measurement of the DRS signal.

13. The system of claim 12, wherein each measurement of the DSCA measurement, the Raman measurement, and the DRS measurement is taken during a respective defined time period, which is optionally constant, for example 5 milliseconds of less.

14. The system of claims 12 or 13, further configured to process each measurement of the DSCA measurement, the Raman measurement, and the DRS measurement together to generate one or more information on the sample.

15. The system of any one of the previous claims, wherein the probe is dimensioned to be held by hand.

16. A method for operating a system according to any of the previous claims, comprising:

- selecting the first mode and carrying out a DSCA measurement of the laser speckle signal;

- selecting a different mode from the first mode and carrying out a second measurement.

17. The method of claim 16, further comprising:

selecting the second mode and carrying out a Raman measurement of the Raman signal.

18. The method of claims 16 or 17, further comprising:

selecting the third mode and carrying out a DRS measurement of the DRS signal.

19. The method of any of the previous claims 16 to 18, wherein (i) the DSCA measurement,

(ii) the Raman measurement or the DRS measurement, and

(iii) optionally the other measurement of the Raman measurement and the DRS measurement not in step (ii);

are carried out in a sequence for a number of repetitions.

20. The method of any of the previous claims, further comprising:

- processing a detection data of the DSCA measurement and at least one of a detection data of the Raman measurement of claim 17 or a detection data of the DRS measurement of claim 18 to a combined processed result, wherein the combined processed result contains a processed information.

21. The method of claim 20, further comprising transforming the processed information into visual form.