Multiple light sources integrated into a neural probe for activation with multiple wavelengths

Abstract

Probe (100) comprising: a probe body (102) suitable for penetrating biological tissue; and a plurality of high-power light sources arranged within the probe body (102), wherein the plurality of the high-power light sources are light-emitting diodes (LEDs), wherein at least one LED emits light in a red or infrared region of the electromagnetic spectrum and at least one LED emits light in a blue, yellow, or green region of the electromagnetic spectrum, wherein the at least one LED emitting light in the red or infrared region of the electromagnetic spectrum comprises: a germanium substrate; at least one doped layer of In0.49Ga0.51P of the n type; at least one undoped layer of In0.49Ga0.51P; a trough layer of InxGa(1-x)P, wherein x is equal to a value between approximately 0.50 and approximately 0.60; and at least one doped layer of In0.49Ga0.51P of the p-type.

Description

BACKGROUND OF THE INVENTIONTechnical FieldThe present invention relates generally to optogenetics and, more particularly, to neural probes having multiple powerful light sources for activating neurons without overheating local tissue.Description of the Prior ArtThe field of optogenetics includes genetically altering organisms to render them photosensitive and to create the ability to selectively direct neurons in living organisms. In this way, optogenetics produce the ability to directly excite and observe certain biological processes within an organism.For exciting neurons, a neural probe is used which contains, for example, a light emitting diode. The light emitting diode irradiates nearby neurons, whereby these neurons are activated. However, this technique is limited by generating heat in the light emitting diode. In particular, the behavior of the nerve tissue can be adversely affected by a temperature rise of only 2° C.Therefore, there is a need to solve the above-mentioned problem.WO 2017 / 004 576 A1 relates to implantable, injectable and / or surface-mounted biomedical devices and related methods for connection to a target tissue. The devices include a substrate, one or more microfluidic channels embedded in or supported by the substrate, and a fluid actuator in operational communication with one or more reservoirs and responsive to a wireless control signal.DE 11 2010 003 700 T5 relates to a light-emitting diode emitting at a wavelength of 390-415 nm, which light-emitting diode has a gallium- and nitrogen-containing base material with an active region.SUN, Xiaojuan, et al., "Short-wavelength light beam in situ monitoring growth of INGaN / GaN green LEDs by MOCVD" Nanoscale research letters, 2012, relates to the production of five-period INGaN / GaN multiple quantum well green light emitting diodes (LEDs) by metalorganic chemical vapor deposition.SUMMARYAccording to a first aspect of the present invention, there is provided a probe comprising: a probe body capable of penetrating biological tissue; and a plurality of high-power light sources disposed within the probe body, wherein each high-power light source has a sufficiently high optical output for exciting a photosensitive reaction in adjacent tissues and the output is not required to be so high that a total amount of heat of the plurality of light sources may result in a spurious temperature rise in the adjacent tissues.According to another aspect of the present invention, there is provided a probe comprising: a probe body suitable for penetrating biological tissues; and a plurality of high-power light emitting diodes (LEDs) disposed within the probe body, wherein at least one LED emits light in a red or infrared region of the electromagnetic spectrum and at least one LED emits light in a blue, yellow or green region of the electromagnetic spectrum, wherein each high-power LED has a sufficiently high optical output to excite a photosensitive response in adjacent tissues, and the output of each LED is not required to be so high that a total amount of heat of the plurality of LEDs could result in a spurious temperature rise in the adjacent tissues.According to another aspect of the present invention, there is provided a probe comprising: a probe body suitable for penetrating biological tissues; and a plurality of high-power light sources disposed within the probe body, having an optical output of at least 10 mW / mm 2 and having a sufficiently low output such that each of the plurality of high-power light sources, when active, causes a temperature rise in adjacent tissues between about 0.022 °C and about 0.041 °C.A probe includes a probe body suitable for penetrating biological tissue. High-power light sources are arranged inside the probe body. Each high-power light source has a sufficiently high optical output for exciting a photosensitive response in adjacent tissues and a sufficiently low optical output such that a total amount of heat of the plurality of light sources does not result in a disturbing temperature rise in the adjacent tissues.A probe includes a probe body suitable for penetrating biological tissue. High-power light emitting diodes (LEDs) are arranged within the probe body. At least one LED emits light in a red or infrared region of the electromagnetic spectrum, and at least one LED emits light in a blue, yellow or green region of the electromagnetic spectrum. Each high power LED has a sufficiently high optical output to excite a photosensitive response in adjacent tissues, and each LED has a sufficiently low output such that a total amount of heat of a plurality of LEDs does not result in a spurious temperature rise in the adjacent tissues.A probe includes a probe body suitable for penetrating biological tissue. High-power light sources are arranged inside the probe body. Each high power light source has an optical output power of at least 10 mW / mm 2 and a sufficiently low output power such that each of the high power light sources in the active state causes a temperature rise in adjacent fabrics between about 0.022 °C and about 0.041 °.These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof when taken in conjunction with the accompanying drawings.The invention is described by the features of the independent claim.BRIEF DESCRIPTION OF THE DRAWINGSThe following description provides details of preferred embodiments with reference to the following figures, wherein: FIG. 1 is a diagram of a neural probe with multiple high power light sources according to an embodiment of the present invention; FIG. 2 is a cross-sectional view of a high power light source according to an embodiment of the present invention; FIG. 3 is a cross-sectional view of a high power light source according to an embodiment of the present invention; FIG. 4 is a block diagram of a probe control system according to an embodiment of the present invention; and FIG. 5 is a block diagram of a processing system according to an embodiment of the present invention.DETAILED DESCRIPTIONEmbodiments of the present invention provide neural probes with high power light sources. These powerful light sources generate less heat than conventional light emitting diodes and allow a plurality of such light sources to be combined into a single probe, each light source emitting a different wavelength. Accordingly, multiple different wavelength sensitivities may be utilized simultaneously, thus providing the ability to selectively activate different sets of neurons using a single probe without causing disruptive increases in tissue temperature.In the following drawings showing neural probe 100, like reference numerals represent the same or similar elements as first shown in Figure 1. The probe 100 includes a probe body 102 having a plurality of high power light sources 104. It should be appreciated that the light sources 104 may be of any suitable type and may be disposed at any suitable location along the length of the probe body 102, but it is particularly contemplated that the light sources 104 in the form of high-power light emitting diodes (LEDs) may be located proximate the probe tip 106. Control / power lines 108 are also shown that supply electrical power to excite the light sources 104 and optionally provide control signals to the light sources 104.It should be appreciated that the probe 102 may be constructed of any suitable biocompatible material, including, for example, glass, sapphire, or titanium, and is designed in shape and size to penetrate living biological tissue. The light sources 104 and control / power lines 108 may be attached to the probe 100 by any suitable biocompatible mechanism (e.g., adhesive or cement) and may be fabricated directly on the probe 100, in accordance with some embodiments. According to an alternative embodiment, the probe may be formed on a printed circuit board, which is then enveloped by a transparent biocompatible material in order that light from the light sources 104 can pass to the surrounding tissues. In particular, it is conceivable that the probe 100 is suitable for penetrating into living tissues, in particular into nerve tissue. Thus, the diameter of the probe 100 should be quite small and the tip 106 of the probe sharp. In addition, the probe body 102 should be sufficiently durable so as not to be damaged upon penetration into such tissues.It has been possible to activate different nerve tissues by different wavelengths and with different light intensities. Exemplary wavelengths for the light sources 104 range from about 1,850 nm to about 2,120 nm, but it should be understood that wavelengths above or below this range may also be used. An excitation threshold corresponds to the energy density required to activate a neuron and may be between about 1.6 mJ / cm 2 and about 16.904 mJ / cm 2 depending on the type of neuron. The light can be used to induce changes in proteins that regulate membrane potentials in the cells by exciting or inhibiting membrane currents. This ability to control cells has been shown to be helpful in preclinical studies and has considerable potential in the treatment of, inter alia, diseases such as parkinsonism, epilepsy, chronic pain, addictive diseases and depression. It should be understood that the present probe 100 can be applied to both humans and animals.FIG. 2 shows an exemplary structure of the light sources 104. According to this embodiment, a low-power LED is used as the light source 104. The layers of the light source 104 may be deposited sequentially by any suitable deposition process, including, for example, chemical vapor deposition (CVD), physical vapor deposition (PVC), atomic layer deposition (ALD), or gas cluster ion beam deposition (GCIB).CVD is a deposition process in which a deposited substance is formed due to a chemical reaction between gaseous reactants at a temperature higher than room temperature (e.g., from about 25° C. to about 900° C.). The solid reaction product is deposited on the surface on which a thin film, a layer system or a layer of the solid is to be formed. Variations of CVD processes include, but are not limited to, atmospheric pressure CVD (APCVD), low pressure CVD (LPCVD), plasma enhanced CVD (PECVD), and metal organic CVD (MOCVD), and combinations thereof may also be used. According to alternative embodiments using PVD, a sputtering device may comprise DC diode systems, high frequency sputtering, magnetron sputtering or sputtering with ionized metal plasma. In alternative embodiments using ALD, chemical species react simultaneously with a surface of a material to deposit a thin film on the surface. In alternative embodiments using GCIB deposition, a high pressure gas is expanded in a vacuum, which subsequently precipitates in clusters. These clusters can be ionized and directed onto a surface, resulting in a highly anisotropic deposition.A semiconductor substrate 202 is formed of a suitable semiconductor material. In the present embodiments, it is primarily assumed that the semiconductor substrate 202 is formed of a III-V compound semiconductor material, but it is understood that a group IV semiconductor material may be used instead. The term "III-V compound semiconductor" refers to a semiconductor material containing at least one element selected from Group III of the Periodic Table of Elements (i.e., Group 13 of IUPAC (International Union of Pure and Applied Chemistry)) and at least one element selected from Group V of the Periodic Table of Elements (i.e., Group 15 of IUPAC). In contrast, Group IV semiconductors are formed from a single element from Group IV of the Periodic Table of the Elements (i.e., Group 14 of IUPAC) such as silicon, germanium and their compounds. Normally, the III-V compound semiconductors are binary, ternary or quaternary alloys containing III / V elements. Examples of III-V compound semiconductors that may be used in the present invention include, but are not limited to, alloys of gallium arsenic, aluminum arsenic, indium gallium arsenic, indium aluminum arsenic, indium aluminum arsenic, indium aluminum arsenic antimony, indium aluminum arsenic phosphorous, indium gallium arsenic phosphorous, cadmium telluride, zinc selenide, and combinations thereof. Examples of Group IV semiconductors that may be used in the present invention include, but are not limited to, silicon, germanium, silicon germanium, silicon germanium carbide, silicon carbide, polysilicon, epitaxially deposited silicon, amorphous silicon, and multilayers thereof.Then, a stack of semiconductor layers is formed on the semiconductor substrate 102. The layers stacked one above the other may be doped according to one of three conductivity types: p-doped, undoped or n-doped. The individual layers may be doped during the deposition process. An undoped semiconductor material is a material without dopants. As used herein, the term "p-type" refers to the addition of impurities to an undoped semiconductor that creates a lack of valence electrons. Exemplary dopants, i.e. impurities, of the p-type are boron, aluminum, gallium and indium in a silicon-containing substrate. As used herein, the term "n-type" refers to the addition of impurities that generate an excess of free electrons in an undoped semiconductor. Exemplary dopants, i.e., n-type impurities, are considered in a silicon-containing substrate, without being limited thereto: antimony, arsenic, and phosphorus. When III-V compound semiconductor materials are used, Group II atoms serve as acceptors, i.e., p-type ones when they occupy the lattice site of a Group III atom, and Group VI atoms serve as donors, i.e., n-type ones when these Group V atoms are substituted. Group IV dopant atoms, such as silicon, have the property that they can serve as acceptors or donors depending on whether they occupy the lattice site of group III or group V atoms.On the substrate 202, an n-type heavily doped semiconductor layer 204 is formed. In particular, it is contemplated that the n-type heavily doped semiconductor layer 204 may be formed of, for example, gallium arsenide having a dopant concentration of about 10 18 cm -3. On the heavily doped n-type semiconductor layer 204, an n-type semiconductor layer of indium gallium phosphorus having a lower dopant concentration of about 10 18 cm -3 is formed. The n-type layer 206 having the lower dopant concentration has an exemplary thickness of about 200 nm.A set of undoped layers is then formed on the n-type layers 204 and 206. A first undoped layer 208 having a thickness of about 50 nm is formed of undoped indium gallium phosphorus. A second undoped layer 210 is formed from undoped indium gallium arsenic. A third undoped layer 212 having a thickness of about 50 nm is formed of undoped indium gallium phosphorus.Then, a set of p-type layers is formed on the undoped layers 208, 210 and 212. On the third undoped layer 212, a first p-type layer 214 of p-doped indium gallium phosphorus having a dopant concentration of about 10 18 cm -3 is formed. The first p-type layer has a thickness of about 200 nm. On the first p-type layer 214, a second heavily doped p-type layer 216 of p-doped gallium arsenide having a dopant concentration of about 10 18 cm -3 is formed. The second p-type layer 216 has a thickness of about 30 nm and serves as an upper electrical contact for the LED 104.With this LED structure, a particularly current-saving high-power light source is provided. Specifically, it was measured that the efficiency of the LED is the highest in the range between 1 μA and about 1 mA. In particular, the light source 10 shown provides an external quantum efficiency in this current range of between approximately 0.9 and 1. The external quantum efficiency is understood to mean the ratio between the number of photons emitted by an LED and the number of electrons flowing through the unit, which expresses the efficiency of the unit for converting injected charges into emitted photons, a value equal to 1 expressing an ideal efficiency. Because of this excellent efficiency, the light sources 104 of the present embodiments exhibit a temperature change in surrounding tissues that is 100 times less than that of conventional probes.FIG. 3 shows another embodiment of the structure for the light sources 104. This structure is particularly suitable for a biocompatible high-power LED which draws only a weak injection current and emits blue, yellow or green light (i.e. light in the blue, yellow or green region of the electromagnetic spectrum). As above, the layers of the light source 104 may be deposited sequentially by a suitable deposition process, including, for example, CVD, PVD, ALD, or GCIB deposition. The light source 104 of FIG. 3 may have quantum efficiencies close to the quantum efficiencies achieved with the light source shown in FIG. 2.A substrate 302 is formed of a material such as gallium nitride or sapphire (e.g., aluminum oxide). A heavily n-doped buffer layer 304 is formed on the substrate 302, for example, of gallium nitride having a thickness between about 20 nm and about 1,000 nm. The heavily n-doped buffer layer 304 may serve as a device lower electrical contact. Then, an n-type semiconductor layer 306 having a lower dopant concentration than the heavily doped buffer layer 304 and having a thickness between about 100 nm and about 1,000 nm is formed on the buffer layer 304. It should be appreciated that a III-V type semiconductor material such as gallium nitride may be doped using silicon as a dopant with a dopant concentration on the order of about 10 18 cm -3 to about 10 20 cm -3. A "heavily doped" layer has a higher conductivity due to a larger number of free charge carriers. Instead of silicon, any other suitable conventional dopant material may be used.Then, a set of undoped layers is formed on the set of n-type layers. A barrier layer 308 of undoped gallium nitride having a thickness between about 20 nm and about 100 nm may be formed. Then, an active layer 310 of indium gallium nitride (In x Ga (1-x) N with x=0.10 to 0.50) is formed with a thickness of about 2 nm to about 10 nm above the barrier layer 208. On the active layer 310, a second barrier layer 312 of undoped gallium nitride is formed with a thickness of about 20 nm to about 100 nm. Then, a p-type gallium nitride film 314 having a thickness between about 100 nm and about 1,000 nm, for example, is formed on the barrier layer 312. The p-type top layer 314 may play the role of a device top electrical contact. Any suitable conventional dopant material may be used to form the p-doped layers.According to an alternative embodiment, the structure of FIG. 3 may be used with different materials to produce a low power LED emitting red or infrared light (i.e., light in the red or infrared region of the electromagnetic spectrum). In such an embodiment, the substrate 302 may be formed of germanium. The buffer layer 304 may be formed of heavily doped n-type indium gallium phosphorus (In 0.49 Ga 0.51 P), and the more lightly doped n-type semiconductor layer 306 may be formed of In 0.49 Ga 0.51 P with a lower dopant concentration. Likewise, the first undoped barrier layer 308 and the second undoped barrier layer 312 may be formed of In 0.49 Ga 0.51 P, while the well layer 310 may be formed of indium gallium phosphorus having a slightly different composition (e.g., In x Ga (1-x) P where x=0.50 to 0.60). Then, the heavily doped p-type semiconductor layer 314 may be formed of In 0.49 Ga 0.51 P.In this embodiment of the light sources 104, biocompatible materials (e.g., gallium nitride or indium gallium phosphorus) are used and biologically hazardous materials (e.g., arsenic) are avoided. The output power required to activate a 100 μm neuron is approximately 10 mW / mm 2. At this level of performance, the light sources 104 embodied by the structure of FIG. 3 are about 10 times to 100 times more efficient than conventional LEDs, thus significantly reducing heating of adjacent tissues. While the temperature rise caused by conventional LEDs is about 2.2° C. to about 4.1° C., the temperature rise caused by the present embodiments is about 100 times lower (e.g., about 0.022 ° C. to about 0.041 ° C.).It should be appreciated that aspects of the present invention are described in terms of a particular illustrative architecture; however, other architectures, structures, substrate materials, and process features and steps may be varied within the scope of aspects of the present invention.It will also be understood that an element such as a layer, region or substrate referred to as being "on" or "above" another element may be directly on the other element or other elements may be interposed therebetween. On the other hand, when an element is referred to as being "directly on" or "directly above" another element, no other elements are interposed therebetween. It will also be understood that an element, when referred to as being "connected" or "coupled" to another element, may be directly connected or coupled to the other element, or may also be other elements therebetween. On the other hand, when an element is referred to as being "directly connected" or "directly coupled" to another element, no other elements are present therebetween.The present embodiments may include an integrated circuit chip design that may be generated in a computer graphical programming language and stored in a computer storage medium (e.g., a floppy disk, a magnetic storage tape, a physical hard disk drive, or a virtual hard disk drive such as a memory access network). When the developer does not fabricate chips or photolithography masks used to fabricate chips, he may transmit the completed design directly or indirectly to such institutions by physical means (e.g., by providing a copy of the storage medium used to store the design) or electronically (e.g., via the Internet). The stored design is then converted to the appropriate format (e.g., GDSII) for fabricating the photolithographic masks, which typically include multiple instances of the particular chip design to be formed on a wafer. The photolithography masks are used to define regions of the wafer (and / or the layers thereon) that are to be etched or otherwise processed.Methods such as those described herein may be used for manufacturing integrated circuit chips. The integrated circuit chips produced in this case can be marketed by the manufacturer in the form of an unprocessed wafer (i.e. as a wafer having a plurality of uncapsulated chips), as individual wafers or in a ready-made form. In the latter case, the chip is incorporated into a single chip package (such as a plastic carrier with traces attached to a motherboard or other parent carrier) or into a multi-chip package (such as a ceramic carrier with surface and / or embedded leads). In either case, the chip is then associated with other chips, discrete circuit elements, and / or other signal processing units as part of either (a) an intermediate product such as a motherboard or (b) an end product. The final product can be any product that includes integrated circuit chips, from toys and other simple applications to powerful computer products with a display, keyboard or other input unit, and a central processor.It should also be understood that material compounds are described in terms of listed elements, e.g., SiGe. These compounds contain different proportions of the elements within the compound such that SiGe contains, for example, Si x Ge 1-x where x is less than or equal to 1, etc. In addition, other elements may also be included in the compound and also function in accordance with the present invention. The compounds with additional elements are referred to herein as alloys.References in the specification to "one embodiment" or "an embodiment," and other such variations, mean that a particular feature, structure, or characteristic described in connection with the embodiment, and so forth, is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in one embodiment," as well as any other variants, in various places throughout the specification are not intended to be necessarily all referring to the same embodiment.It should be appreciated that the use of, for example, " / ", "and / or" and "at least one of" in the cases "A / B", "A and / or B" and "at least one of A and B) is intended to mean only the selection of the first listed option (A), only the selection of the second listed option (B), or the selection of both options (A and B). Another example states that in the cases "A, B and / or C" and "at least one of A, B and C" only the selection of the first listed option (A) or only the selection of the second listed option (B) or only the selection of the third listed option (C) or only the selection of the first and second listed options (A and B) or only the selection of the first and third listed options (A and C) or only the selection of the second and third listed options (B and C) or the selection of all three options (A and B and C) is meant. It will be apparent to those skilled in this or related art that this can be extended to many listed items.The terms used herein are used only to describe individual embodiments and are not intended to mean a limitation to exemplary embodiments. The singular forms "a", "an" and "the" used herein are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, it is understood that the terms "comprises," "includes," and / or "including" used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.Spatial relative terms such as "below," "below," lower," "above," "upper," and the like may be used herein to more easily describe a relationship of an element or feature to one or more other elements or features depicted in the FIGURES. It is understood that the spatial relative indications are intended to include various orientations during use or operation in addition to the orientation depicted in the FIGURES. For example, when the unit in the FIGURES is turned on head, elements described as "below" other elements or features or "below" are "above" the other elements or features. Thus, the term "below" may include the two orientations above and below. The unit may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative terms used herein may be construed accordingly. It will also be understood that a layer, when referred to as being "between" two layers, is the only layer between the two layers or that one or more intermediate layers may also be present.It is understood that although the terms first, second, etc. may be used herein to describe various elements, these elements are not intended to be limited thereto by these terms. These terms are used only to distinguish one element from another element. Thus, a first element discussed below may also be referred to as a second element without departing from the scope of the present invention.FIG. 4 shows a probe control system 400. The probe control system 400 includes a hardware processor and memory 404. A probe interface 406 provides a physical communication interface between the probe control system 400 and the probe 100. A power source 408 supplies electrical power to the probe 100 via the probe interface 406 and may be in the form of a battery or other DC power source or alternatively may include suitable circuitry for converting AC power to a form suitable for the probe 100. In particular, it is contemplated that probe interface 406 may have a connection line to probe 100 that provides electrical power and control signals, but it is also contemplated that a wireless interface may be used in embodiments where the probe has a local power source. According to other embodiments, the probe control system 400 may be directly incorporated into the body of the probe 100.In some embodiments, a probe control module 408 is implemented in the form of software stored in the memory 404 and executed by the processor 402. According to other embodiments, the probe control module 408 may be implemented by one or more discrete hardware components, e.g., in the form of application specific integrated chips or field programmable gate arrays. The probe control module 408 sends command signals to the probe(s) 100 via the probe interface 406 and may be used to enable and disable individual light sources 104 and to control their optical output power. It should be appreciated that the probe control module 408 may issue these commands at the expense of an operator, or alternatively, automatically.FIG. 5 shows an example processing system 500 that may represent the transmitting unit 100 or the receiving unit 120. The processing system 500 includes at least one processor (CPU) 504 operatively connected to other components by a system bus 502. A cache memory 506, a read only memory (ROM) 508, a random access memory (RAM) 510, an input / output (I / O) adapter 520, a sound adapter 530, a network adapter 540, a user interface adapter 550, and a screen adapter 560 are operatively connected to the system bus 502.A first storage unit 522 and a second storage unit 524 are connected to the system bus 502 through the I / O adapter 520. The storage units 522 and 524 may be a disk storage drive (e.g., a magnetic or optical disk storage drive), a magnetic solid state storage medium, and so forth. The storage drives 522 and 524 may be storage drives of the same type or of different types.A speaker 532 is operatively connected to the system bus 502 through the sound adapter 530. A transceiver 542 is connected to the system bus 502 through the network adapter 540. A display unit 562 is connected to the system bus 502 through the display adapter 560.A first user input unit 552, a second user input unit 554, and a third user input unit 556 are operatively connected to the system bus 502 through user interface adapters 550. The user input units 552, 554, and 556 may be a keyboard, a mouse, a number block, an image acquisition unit, a motion tracking unit, a microphone, a unit for executing the functionality of at least two of the foregoing units, and so forth. Of course, other types of input units may be used as long as the scope of the present invention is maintained. The user input units 552, 554, and 556 may be user input units of the same type or different types. The user input units 552, 554, and 556 are used to input information to and output information from the system 500.It will be apparent to those skilled in the art that processing system 500 may of course also include other elements (not shown) and may not include certain elements. It is also plausible for the skilled person that, depending on the specific design of the processing system 500, various other input units and / or output units can be contained in the latter. For example, various types of wireless and / or wired input and / or output units may be used. Those skilled in the art would be plausible that other processors, controllers, memories, and so forth may also be used in various arrangements. Based on the teachings of the present invention provided herein, these as well as other variations of the processing system 500 are evident.Having described preferred embodiments of multiple light sources integrated into a neural probe for activation at multiple wavelengths (which are for illustrative purposes only and are not intended to be limiting), it is to be understood that modifications and variations can be made by one skilled in the art based on the above teachings. It should therefore be understood that changes may be made to the individual embodiments which are within the scope set forth by the appended claims.

Claims

A probe (100) comprising: a probe body (102) suitable for penetrating biological tissue; and a plurality of high power light sources disposed within the probe body (102), wherein the plurality of high power light sources are light emitting diodes (LEDs), wherein at least one LED emits light in a red or infrared region of the electromagnetic spectrum and at least one LED emits light in a blue, yellow or green region of the electromagnetic spectrum, wherein the at least one LED emitting light in the red or infrared region of the electromagnetic spectrum comprises: a germanium substrate; at least one doped layer of n-type In 0.49 Ga 0.51 P; at least one undoped layer of In 0.49 Ga 0.51 P; a well layer of In x Ga (1-x) P, where x is equal to a value between about 0.50 and about 0.60; and at least one doped layer of p-type In 0.49 Ga 0.51 P.

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