Vibrating polarization beam splitter for improved return light detection

Abstract

A vibrating polarization beamsplitter for improved return light is disclosed. An example method can involve emitting, by an emitter, a first light pulse and reflecting, by a polarization beamsplitter in a first position, the first light pulse, where the polarization beamsplitter is at a first angle of incidence in the first position. The example method can also involve adjusting, after the polarization beamsplitter reflects the first light pulse, a position of the polarization beamsplitter from the first position to a second position, where the polarization beamsplitter is at a second angle of incidence in the second position. The example method can also involve transmitting, by the polarization beamsplitter, a return light pulse through the polarization beamsplitter, the return light pulse based on the first light pulse. The example method can also involve detecting, by a detector, the return light pulse.

Description

Background Technology

[0001] In a LiDAR system (e.g., a vehicle LiDAR system), a transmitter can be used to emit light pulses into the environment. These light pulses can be reflected back to the LiDAR system from objects in the environment, and the LiDAR system's detectors can detect the returned light. The timing of the detected returned light can then be used to determine the distance of the object relative to the LiDAR system. In some cases, the LiDAR system may also include a reflective element for reflecting the emitted light back into the environment. For example, the reflective element might be a mirror and can be used in coaxial LiDAR systems to address parallax problems that may occur in other types of LiDAR systems. However, a potential drawback of using such a reflective element is that it may also be deployed in the path of the detector. Given this, the reflective element could potentially prevent the returned light pulses from reaching the detector (because the returned light might be reflected from the reflective element and move away from the detector). To address this issue, a polarization beamsplitter can be used instead of a standard mirror as the reflective element. A polarization beamsplitter can provide the benefit of reflecting light of certain polarization states while allowing light of other polarization states to pass through. As an example, a polarization beamsplitter can reflect s-polarized light and allow p-polarized light to pass through. Since the reflected light from an object can be a mixture of s-polarized and p-polarized light, a polarization beamsplitter can allow some of this reflected light to pass through to the detector (e.g., p-polarized light). However, s-polarized light may still be reflected from the polarization beamsplitter and never reach the detector. Therefore, in the best-case scenario, approximately half of the reflected light is lost, while in the worst-case scenario, no light passes through the polarization beamsplitter to the detector device. This reduces the amount of reflected light detected by the detector. Consequently, the overall efficiency of the system in detecting reflected light may decrease. Attached Figure Description

[0002] A detailed description is given with reference to the accompanying drawings. The drawings are provided for illustrative purposes only and depict only exemplary embodiments of this disclosure. The drawings are provided to facilitate understanding of this disclosure and should not be construed as limiting the breadth, scope, or applicability of this disclosure. In the drawings, the leftmost position(s) of the reference numerals identify the first appearance of the reference numeral. The same reference numerals are used to indicate similar but not necessarily identical or completely identical components. However, different reference numerals may also be used to identify similar components. Various embodiments may utilize elements or components different from those shown in the drawings, and some elements and / or components may not be present in various embodiments. Depending on the context, the use of singular terms to describe components or elements may encompass multiple such components or elements, and vice versa.

[0003] Figures 1A-1C An example schematic diagram of a vibration polarization beam splitter system according to one or more example embodiments of the present disclosure is depicted.

[0004] Figure 2 Example graphs depicting the transmission and reflection intensities at various angles based on a polarization beamsplitter according to one or more example embodiments of the present disclosure are provided.

[0005] Figure 3 Example diagrams depicting various characteristics of a LIDAR system at different times according to one or more example embodiments of the present disclosure.

[0006] Figure 4 Example methods according to one or more example embodiments of this disclosure are described.

[0007] Figure 5 An example LIDAR system architecture according to one or more example embodiments of this disclosure is described. Detailed Implementation

[0008] Overview

[0009] This disclosure relates in particular to systems and methods for improving return light detection in a LIDAR system using a vibrating polarization beamsplitter. At a high level, a LIDAR system may include at least one or more transmitter devices for generating emitted light, one or more detector devices for detecting return light generated due to reflection of the emitted light from objects in the environment, and one or more polarization beamsplitters (hereinafter referred to as "transmitter device," "detector device," or "polarization beamsplitter," but such references can similarly apply to any number of such components). More specifically, this disclosure may relate to a LIDAR system in which the position of a polarization beamsplitter is selectively changed from a first position to a second position using an actuator to improve return light detection in the LIDAR system. As described above, some LIDAR systems may employ polarization beamsplitters. Depending on the polarization state of the light in contact with the polarization beamsplitter, light may be reflected from and / or transmitted through the polarization beamsplitter. For illustrative purposes, a polarization beamsplitter may reflect s-polarized light, which may be desirable if the transmitter device of the LIDAR system emits s-polarized light (such that the emitted light can be reflected back into the environment and towards objects). However, in addition to the path of light emitted from the transmitter device in a LIDAR system, a polarization beamsplitter can also be present in the path of any returning light reflected from an object in the environment. This can be problematic because any returning light in the same polarization state as the emitted light (e.g., s-polarized light continuing the example above) might again be reflected from the polarization beamsplitter and away from any detector device present in the LIDAR system. This returning light might then be lost (e.g., never detected by the detector device), and thus the LIDAR system might not receive as much information about the object as it would if the light instead passed through the polarization beamsplitter and was directed towards the detector device. It should be noted that while this description refers to reflecting emitted light from the polarization beamsplitter and transmitting returning light through it, the opposite can apply depending on the configuration of the transmitter device and / or detector device in the LIDAR system. That is, the LIDAR system can also be configured to emit light through the polarization beamsplitter and reflect returning light back towards the detector device. While for simplicity the systems and methods described herein may be described in certain sections only for one of these transmitter / detector device configurations, it should be noted that the systems and methods are also applicable to any other transmitter / detector device configuration. Furthermore, while any example herein may describe the emission of s-polarized light and the return of both s-polarized and p-polarized light, p-polarized light may alternatively be emitted in some cases.

[0010] In some embodiments, the systems and methods described herein address the problem of “lost” light reflected from a polarization beamsplitter by actuating a polarization beamsplitter at one or more different locations throughout the cycle of emitting and receiving the returned light. These one or more locations may correspond to the polarization beamsplitter being at different angles relative to a reference frame at different times. This actuation of the polarization beamsplitter can be used to address the problem of lost light because the characteristics of the polarization beamsplitter allow the amount of light in different polarization states reflected from and / or transmitted through the beamsplitter to vary depending on the incident angle of the beamsplitter. For example, when the beamsplitter is at a first angle, 90% of p-polarized light can be transmitted through the beamsplitter, while 40% of s-polarized light can be transmitted through it. When the beamsplitter is at a second angle, 100% of p-polarized light can be transmitted through and 0% of s-polarized light can be transmitted through it. These examples are not intended to be limiting, and the actual percentage of light reflected from and / or transmitted through the beamsplitter can vary. If the emitted light is s-polarized and the returned light is mixed-polarized (e.g., s-polarized and p-polarized), then two angles can be chosen such that the first angle results in a large reflection of the s-polarized light, while the second angle results in a high percentage of transmission of both s-polarized and p-polarized light through the polarization beam splitter.

[0011] In some embodiments, rotation of the polarization beamsplitter can be achieved using an actuator. In some instances, the actuator can be a voice coil motor. In other instances, the actuator can be another type of motor, such as a stepper motor, a brushed motor, a brushless motor, or any other type of motor. To achieve resonance of the polarization beamsplitter between two angles, a spring can be attached to one side of the polarization beamsplitter and a motor can be attached to the other side of the polarization beamsplitter (e.g., as shown in the image). Figures 1B-1C(As depicted in the text). In such cases, resonance can therefore be passively performed by a spring, where a motor is used to compensate for losses. Resonance can also be performed by electrostatic or piezoelectric forces or signals from a computing system (i.e., the vibration of the polarization beamsplitter can also be actively controlled by signals from a controller). In some embodiments, to describe in more detail the entire process involving the vibration of the polarization beamsplitter, the transmitter device of the LIDAR system can emit light toward the polarization beamsplitter. The light emitted by the transmitter device can be polarized (e.g., the emitted light can be s-polarized, but can also be in any other polarization state or combination of polarization states). The polarization beamsplitter can be deployed in the path of the emitted light such that the emitted light travels from the transmitter device to the polarization beamsplitter. When the light is emitted from the transmitter device, the polarization beamsplitter can be in a first position, with the emitted light striking the polarization beamsplitter at a first angle of incidence. The polarization beamsplitter at the first angle can cause the s-polarized emitted light to be reflected from the polarization beamsplitter into the environment of the LIDAR system. The emitted light can then travel through the environment until it is reflected from objects in the environment and reflected back toward the LIDAR system. This returned light can include a mixture of polarization states (e.g., p-polarized and s-polarized). While it might be desirable for the emitted light to be reflected from the polarization beamsplitter so that it can travel into the environment, this reflection might not be desirable for the returned light. This is likely because, from the perspective of the returned light, the detector device might be positioned behind the polarization beamsplitter (e.g., aligned on the same path as the returned light), and it might be desirable for as much returned light as possible to reach the detector device so that the LIDAR system can receive as much returned light as possible from objects in the environment. With the polarization beamsplitter in the first position, p-polarized returned light can pass through the polarization beamsplitter and be received by the detector device. However, at least some of the s-polarized returned light can be reflected away from the detector device from the polarization beamsplitter. Therefore, if the polarization beamsplitter remains in the first position, some of the returned light will be lost.

[0012] In some embodiments, to compensate for the loss of s-polarized return light reflected from the polarization beamsplitter and away from the detector device, the polarization beamsplitter can be rotated to a second position after the emitted light pulse is reflected into the environment. As described above, in the second position, the polarization beamsplitter can be oriented at a different angle than in its first position. The characteristics of the polarization beamsplitter allow that when it is oriented at the second angle, most (e.g., up to 90% or more) of the s-polarized light can be transmitted through the polarization beamsplitter instead of being reflected away from the polarization beamsplitter and thus away from the detector device (the transmission and / or reflection amounts of the polarization beamsplitter with respect to s-polarized and p-polarized light can be referenced below). Figure 3(Further description). That is, by rotating the polarization beamsplitter to a second position after the emitted light from the transmitter device is reflected into the environment, more returning light can pass through the polarization beamsplitter upon return to reach the detector device, and thus the detector device of the LIDAR system can collect more data from the environment. Furthermore, the degree difference between the first and second angles can be relatively small. For example, the difference can be on the order of 1 to 2 degrees, and generally between 1 and 10 degrees. In one example, the first angle could be 45 degrees and the second angle could be 43.5 degrees. Because the degree difference between the first angle in the first position and the second angle in the second position is small, actuation of the polarization beamsplitter between these two positions can be performed quickly. That is, rotating back and forth between the two angles, so that the polarization beamsplitter is in the first position when light is emitted, in the second position when the returned light is received, and then returns to the first angle when the transmitter performs subsequent light emission. Therefore, the polarization beamsplitter can effectively oscillate or vibrate at a high frequency between the first and second positions as light pulses are emitted by the transmitter device and return from the environment as returning light. This small degree of positioning change and the ability of the polarization beamsplitter to actuate very quickly between two locations can be important because the polarization beamsplitter may need to actuate fast enough to keep up with light emission moving at the speed of light. To further increase the vibration speed, multiple smaller polarization beamsplitters can be used instead of a single polarization beamsplitter. Compared to a single, larger polarization beamsplitter, smaller polarization beamsplitters can be rotated and changed angles much faster.

[0013] In some embodiments, the polarization beamsplitter can instead rotate in the same direction to achieve a first angle and a second angle, rather than vibrating between the two angles. This can be achieved by rotating the polarization beamsplitter in the same direction starting from the first angle and then in successive steps of 360 degrees plus the angle difference between the first and second angles and 360 degrees minus the angle difference between the first and second angles. This is easier in practice because it can be achieved without reversing the polarity of the signal driving the motor. This is applicable to cases where the polarization beamsplitter is driven by a non-vibrating motor (e.g., a motor other than a voice coil motor). Furthermore, in such cases, the polarization beamsplitter can be able to rotate much more than the 1 to 10 degrees described above.

[0014] Turn to the attached diagram. Figure 1A Includes example LIDAR system 100 (which can be compared with the following about Figure 5The schematic diagram of the described LIDAR system 500 (which is the same as any other LIDAR system described herein) may include a vibrating polarization beamsplitter 112, which may be described in further detail below. The example LIDAR system 100 may also include at least one or more transmitting devices 108 (e.g., transmitting devices 108a, 108b, and / or 108c) and one or more detector devices 110 (e.g., detector devices 110a, 110b, and / or 110c). For simplicity, “transmitter device 108” and / or “detector device 110” may be referred to hereinafter; however, such descriptions may similarly apply to any number of transmitter devices 108 and / or detector devices 110. In some embodiments, the LIDAR system 100 may be integrated with a vehicle 102 and may be used at least to provide range determination for the vehicle 102. For example, the vehicle 102 may traverse an environment 104 and the LIDAR system 100 may be used to determine the relative distances of various objects 106 in the environment 104 relative to the vehicle 102. Using a vibrating polarization beamsplitter 112 within the example LIDAR system 100 can enhance the LIDAR system 100's ability to perform distance determination. The vibrating polarization beamsplitter 112 can enhance the LIDAR system 100's ability to maximize the amount of light transmitted from object 106 to object 106 that is to be received by one or more detectors 110 within the LIDAR system 100, as light is reflected back from object 106 toward the LIDAR system 100. It should be noted that while the vibrating polarization beamsplitter 112 can... Figure 1A The vibration polarization beam splitter 112 is described as being integrated into vehicle 102, but it can also be implemented in other LIDAR systems besides vehicle LIDAR systems and can also be used outside of the LIDAR context.

[0015] In some embodiments, one or more transmitter devices 108 may include one or more devices for emitting light (e.g., emitting light 118a and / or emitting light 118b) from the LIDAR system 100 and into the environment 104. Figure 1AAs depicted herein, emitted light 118a can be light emitted from transmitter device 108 toward vibrating polarization beamsplitter 112, and emitted light 118b can be the result of emitted light 118a being reflected from vibrating polarization beamsplitter 112 into environment 104. For simplicity, the term "embedded light 118" may be used herein, which can refer to either emitted light 118a or emitted light 118b. For example, transmitter device 108 may be a laser diode. In some instances, emitted light 118 may be in the form of a series of pulses. Depending on the configuration of transmitter device 108, emitted light 118 may be in a specific polarization state. The example transmitter device 108 described herein may emit s-polarized light. However, this polarization state of emitted light 118 may be used only for the purpose of consistently describing the operation of vibrating polarization beamsplitter 112 herein, and any other polarization state and / or combination of polarization states of emitted light 118 may also apply. After being emitted from LIDAR system 100 and entering environment 104, emitted light 118 can then be reflected from objects 106 in environment 104 and returned to LIDAR system 100 as return light 120. Although Figures 1A-1C It is possible to describe only one optical pulse 118 emitted by transmitter device 108, but transmitter device 206 may also emit multiple optical pulses 118. In some instances, the optical pulse 118 may be emitted at a fixed wavelength falling within the range of 880-930 nm, but it may also include any other wavelength. However, in some instances, the wavelength of the optical pulse 118 may also be variable. Additional characteristics of the optical pulse 118 may also be fixed and / or variable. For example, the amplitude of the pulse may also be fixed and / or variable.

[0016] In some embodiments, one or more detector devices 110 may include photodiodes for detecting reflected light 120 that has been reflected from an object 106 (e.g., vehicle 106c) in the environment 104. The photodiode may specifically include an avalanche photodiode (APD), which in some instances can operate in Geiger mode. However, any other type of photodetector may also be used. One or more detector devices 110 may be arranged in an array to create a continuous field of view (FOV) for the LIDAR system. An example array configuration may include a two-dimensional (2D) array of 16x2 detector devices 110. The functionality of the detector devices 110 in capturing the reflected light 120 from the environment 104 can be used to allow the LIDAR system 100 to determine information about the object 106c in the environment 104. That is, the LIDAR system 100 may be able to determine information such as the distance of the object 106c from the vehicle 102 and the shape and / or size of the object 106c, as well as other information. In some embodiments, the reflected light 120 reflected from the object 106c in the environment 104 may be mixed-polarized. That is, the reflected light 120 from object 106c can be a combination of polarization states rather than a single polarization state of emitted light 118.

[0017] In some embodiments, the vibrating polarization beamsplitter 112 may be a polarization beamsplitter device configured to rotate about a fixed point 113. In some instances, the fixed point 113 may be located at the center of the vibrating polarization beamsplitter 112 (the fixed point 113 may also be located at any other point along the vibrating polarization beamsplitter 112). Figures 1B-1CThe description is further elaborated. Light (e.g., emitted light 118 and / or reflected light 120) can interact with the vibrating polarization beamsplitter 112 in different ways depending on its polarization state. For example, depending on the polarization state, light can either be reflected from or transmitted through the vibrating polarization beamsplitter 112. Furthermore, the vibrating polarization beamsplitter 112 may not necessarily reflect all light of one polarization state and transmit all light of another polarization state, but may instead transmit and / or reflect a certain percentage of light of each polarization state. As an example of this concept, the vibrating polarization beamsplitter 112 may reflect 60% of p-polarized light and transmit 40% of p-polarized light, and may also reflect 30% of s-polarized light and transmit 70% of s-polarized light. Moreover, the percentage of light in a particular polarization state reflected and / or transmitted by the vibrating polarization beamsplitter 112 can be a factor of the angle of incidence of the vibrating polarization beamsplitter 112. This angle of incidence can refer to the angle at which light strikes the vibrating polarization beamsplitter 112. That is, the angle of incidence can refer to the angle between the surface normal and the direction of light. Therefore, the way light interacts with the vibrating polarization beamsplitter 112 can depend not only on the characteristics of the vibrating polarization beamsplitter 112 itself, but also on the relative angle between the vibrating polarization beamsplitter 112 and the beamsplitter. This can be particularly important because it is expected that the emitted light 118 and the returned light 120 will interact with the vibrating polarization beamsplitter 112 in different ways. For example, based on... Figure 1A The relative positioning of the transmitter device 108 and the detector device 110 depicted in the diagram allows for the expectation that the emitted light 118 will be reflected from the vibrating polarization beamsplitter 112 into the environment. It is also expected that the reflected light 120 from the environment will transmit through the vibrating polarization beamsplitter 112 to travel toward and be detected by the detector device 110. The more reflected light 120 from the object 106c in the environment reaches the detector device 110, the more information the LIDAR system 110 will have for more efficient distance determination of the object 106c.

[0018] In some embodiments, rotation of the vibrating polarization beamsplitter 112 can be performed in any suitable manner that provides the required accuracy and speed. For example, an actuator can be used to rotate the vibrating polarization beamsplitter 112. In some instances, the actuator can be a voice coil motor. In other instances, the actuator can be another type of motor, such as a stepper motor, a brushed motor, a brushless motor, or any other type of motor. To achieve resonance of the polarization beamsplitter between two angles, a spring can be attached to one side of the polarization beamsplitter, and a motor can be attached to the other side of the polarization beamsplitter (e.g., as shown in the image). Figures 1B-1C(As depicted in the text). In such cases, resonance can therefore be passively performed by a spring, where a motor is used to compensate for losses. Resonance can also be performed by electrostatic or piezoelectric force or by a signal from a computing system (i.e., the vibration of the polarization beamsplitter can also be actively controlled by a signal from a controller). The frequency of rotation between the first position 112a and / or the second position 112b can also correspond to the frequency at which the transmitter device 108 emits light into the environment 104. This allows the vibrating polarization beamsplitter 112 to rotate from the first position 112a to the second position 112b and return to the first position 112a before each subsequent light emission from the transmitter device 108. The method for controlling the rotation of the vibrating polarization beamsplitter 112 can be referred to in the description below. Figures 1B-1C To describe in more detail (for example, actuation can be passively performed using a motor and a spring).

[0019] In some embodiments, by taking into account the amount of light of a particular polarization state reflected from and / or transmitted through the vibrating polarization beamsplitter 112 based on a change in its angle of incidence, the vibrating polarization beamsplitter 112 can be operated to achieve both the reflection of emitted light 118 and the transmission of returned light 120. For example, when light is emitted from the transmitter device 108 (before the emitted light 118 reaches the vibrating polarization beamsplitter 112), the vibrating polarization beamsplitter 112 can be positioned at a first angle. (This angle) And the angle described below Can be in Figure 1B and 1C The first position 112a (as depicted in the diagram) is in the first angle. In some instances, the first angle can be 45 degrees. When the vibrating polarization beamsplitter 112 is at the first angle, it can be able to reflect all or most of the s-polarized light arriving at it. The emitted light 118 from the transmitter device 108 can be s-polarized, meaning that all or almost all of the emitted light 118 can therefore be reflected from the vibrating polarization beamsplitter 112 and enter the environment 104. After the emitted light is reflected from the vibrating polarization beamsplitter 112 (as shown at 118b) and enters the environment 104, the vibrating polarization beamsplitter 112 can be rotated to a second angle. The second position 112b. In some instances, the second angle can be 43.5 degrees. That is, the difference between the first angle and the second angle can be relatively small (e.g., less than two degrees). This allows the vibrating polarization beamsplitter 112 to actuate rapidly between the first position 112a and the second position 112b. This can be advantageous because the vibrating polarization beamsplitter 112 may need to perform actuation fast enough to effectively keep up with the cycle of emitted and returned light traveling at the speed of light. When the vibrating polarization beamsplitter 112 is at the second angle, it can be able to transmit all or most of the s-polarized light and also transmit all or almost all of the p-polarized light. That is, at the first angle At the second angle, the vibrating polarization beam splitter 112 can reflect all or most of the s-polarized light. Under these conditions, the vibrating polarization beamsplitter 112 is capable of transmitting all or most of the s-polarized light. Therefore, during the cycle of emitting the emitted light 118 into the environment and receiving the light reflected from the object 106c as the return light 120, the rotation of the vibrating polarization beamsplitter 112 allows both transmission from the transmitter device 108 and reception at the detector device 110 to be performed. It should be noted that the first angle of 45 degrees and the second angle of 43.5 degrees are merely exemplary, and any other combination of angles may be used. For example, the first angle could be 42 degrees and the second angle could be 40.5 degrees.

[0020] Figure 1B and Figure 1C Examples can be given when the vibrating polarizing beam splitter 112 is at different angles (e.g., the first angle). Second angle At this time, how can light of different polarization states interact differently with the vibrating polarization beam splitter 112? In particular, Figure 1B It can be described that when the vibrating polarization beam splitter 112 is at the first angle (In the first position 112a), the light interacts with the vibrating polarization beamsplitter 112. As shown, the emitted light 118 from the transmitter device 108 can be reflected from the vibrating polarization beamsplitter 112. This is because the emitted light 118 can be s-polarized and the vibrating polarization beamsplitter 112 can be reflected from the first position 112a. All or most of the s-polarized light is reflected from the first position 112a. This light can be reflected from the vibrating polarization beamsplitter 112 and enter the environment 104, as shown at 118b. As described above, any returning light from the environment can return with mixed polarization. That is, while the emitted light 118 can be, for example, s-polarized, the returning light reflected from the object 106c can return with multiple polarization states (e.g., the returning light can be circularly polarized and / or elliptically polarized, and can include s-polarized returning light 120a and p-polarized returning light 120b). Therefore, if the vibrating polarization beamsplitter 112 is held at the first angle... In the first position 112a, the s-polarized return light 120a can be reflected from the vibrating polarization beamsplitter 112, and the p-polarized return light 120b can be transmitted through the vibrating polarization beamsplitter 112 and toward the detector device 110. This means that the s-polarized return light 120a may never be detected by the detector device 110, thus the LIDAR system 100 will lose some of the return light reflected from the object 106c in the environment. As a result, the LIDAR system 110 may not receive as much information about the object 106c as possible, which will lead to less effective distance determination.

[0021] Figure 1C It can be described when the vibrating polarization beam splitter 112 is at the second angle (In the second position 112b) the light interacts with the vibrating polarization beamsplitter 112. As shown, emitted light 118 from transmitter device 108 can be reflected from the vibrating polarization beamsplitter 112. This is because emitted light 118 can be s-polarized and the vibrating polarization beamsplitter 112 can reflect all or most of the s-polarized light in the first position 112a at the first angle. This light can be reflected from the vibrating polarization beamsplitter 112 and enter the environment 104, as shown at 118b. As mentioned above, any returning light from the environment can return in a mixed polarization state. That is, although emitted light 118 can be, for example, s-polarized, the returning light reflected from object 106c can return in multiple polarization states (e.g., s-polarized returning light 120a and p-polarized returning light 120b). Although s-polarized light will be reflected from the vibrating polarization beamsplitter 112 when it is in the first position, when the vibrating polarization beamsplitter is in the second angle... In the second position 112b, both the p-polarized return light 120b and most or all of the s-polarized return light 120a can be transmitted through the vibrating polarization beamsplitter 112 and toward the detector device 110. Therefore, significantly more return light (e.g., p-polarized return light 120b and s-polarized return light 120a) can be transmitted through the vibrating polarization beamsplitter 112 and toward the detector device 110.

[0022] Figures 1B-1C An example actuator that can be used to drive the rotation of the vibrating polarization beam splitter 112 is also depicted. Figures 1B-1CIn the example depicted, the actuator may include a motor. The motor may be a voice coil motor, such as a stepper motor, brushed motor, brushless motor, or any other type of motor. The motor may be located at one end of the polarization beamsplitter 112. Additionally, a spring may be located at the other end of the polarization beamsplitter 112. A pivot point (e.g., the aforementioned fixed point 113) may exist along the polarization beamsplitter 112 between the motor and the spring. The spring may be tuned using a mirror mass and the pivot point 113 and may be designed to resonate at a set frequency. Resonance allows the polarization beamsplitter 112 to rotate between two extremes, which may be a first position 112a and a second position 112b. The motor may be used to drive the resonant frequency to overcome losses in the spring. The actuator may also include an encoder. The encoder may be optical, magnetic, or may be integrated into the motor itself. The encoder may provide the LIDAR system 100 with information about the position of the polarization beamsplitter 112. Based on this information, the transmitter device 108 may be able to emit light when the polarization beamsplitter is at a first angle. In some instances, when resonance is passively executed, this can be used for the initial transmission from transmitter device 108, and subsequent transmissions can be based on a specific frequency aligned with the actuator's resonant frequency. However, in other cases, transmitter device 108 can alter the timing of the transmission based on information from the encoder. For example, if the timing of the resonance of polarization beamsplitter 112 is changed.

[0023] It should be noted again that while the examples provided herein describe a transmitter emitting s-polarized light and a return beam including both p-polarized and s-polarized light, any combination of any type of polarized light can be similarly substituted. For example, if p-polarized light is emitted from the transmitter, then a first position 112a of the vibrating polarization beamsplitter 112 will be selected such that the p-polarized light is reflected from the vibrating polarization beamsplitter 112.

[0024] Illustrative diagrams and processes

[0025] Figure 2Example graph 200 depicts various transmission and reflection intensities of s-polarized and p-polarized light relative to a polarizing beamsplitter, based on the beamsplitter's angle. The x-axis of graph 200 can represent the angle of incidence of the polarizing beamsplitter, and the y-axis can represent either the intensity of transmission or reflection (e.g., the percentage of light transmitted through or reflected from the polarizing beamsplitter, respectively). Graph 200 may include two separate plots. A first plot 202 may represent the amount of s-polarized light reflected, and a second plot 204 may represent the amount of p-polarized light transmitted. For example, an angle of incidence of 45 degrees may correspond to an intensity value of 1.0 on both plot 202 and plot 204. This could mean that at an angle of incidence of 45 degrees, 100% of the p-polarized light can be transmitted through the polarizing beamsplitter, and 100% of the s-polarized light can be reflected away from the beamsplitter. This can be desirable when a light pulse (e.g., as s-polarized light) is emitted from a transmitting device and needs to be reflected from the polarizing beamsplitter into the environment. Therefore, 45 degrees can be chosen as the first incident angle as described above. Furthermore, graph 200 also shows that an incident angle of approximately 43.5 degrees can result in a transmission intensity value of 1.0 for p-polarized light, as shown in graph 204, and can also result in a reflection intensity value of 0.0 (or close to 0.0) for s-polarized light, as shown in graph 202. That is, when the incident angle of the polarization beamsplitter is 43.5 degrees, most or all of the p-polarized light can be transmitted through the polarization beamsplitter, and most or all of the s-polarized light can also be transmitted through the polarization beamsplitter. This is desirable when the returning light, including both s-polarized and p-polarized light, returns after reflection from objects in the environment of the LIDAR system and may need to be transmitted through the polarization beamsplitter and enter the detector. Therefore, approximately 43.5 degrees can be selected as the second incident angle as described above.

[0026] Figure 3 Includes example plots depicting various characteristics of the LIDAR system at different times. In particular, Figure 3 Four different plots are depicted (plot 301, plot 320, plot 340, and plot 360). The x-axis on each of the four plots can represent time, and all x-axis on the four plots can be the same. That is, the time at a certain position on the x-axis of plot 301 can be the same time at the same position on the x-axis of plot 320, etc.

[0027] In some embodiments, drawing 301 depicts the change of the incident angle of the polarization beamsplitter over time. For example, the polarization beamsplitter may be at a first incident angle (e.g., approximately 45 degrees) during a first time period 302. The first time period may represent the period before a light pulse emitted from the laser arrives at the polarization beamsplitter. At a first transition time 304, the polarization beamsplitter may transition from the first incident angle to a second incident angle (e.g., approximately 43.5 degrees). This first transition time 304 may correspond to the time after a light pulse emitted from the laser of the LIDAR system has been reflected from the polarization beamsplitter and entered the environment, as described above. The polarization beamsplitter may remain at a second incident angle during a second time period 306. The second time period 306 may correspond to the time between the reflection of the emitted light pulse from the polarization beamsplitter and the return light returning from the environment to the polarization beamsplitter. The incident angle may then transition back to the first incident angle at a second transition time 308 to prepare for a subsequent light pulse emitted from the laser of the LIDAR system. This process may be iterative, as shown in drawing 301.

[0028] In some embodiments, drawing 320 depicts the timing of optical pulses from a laser in a LIDAR system as the incident angle relative to the polarization beamsplitter changes.

[0029] In some embodiments, Figures 340 and 360 depict the transmittance and reflectance of s-polarized light through a polarization beamsplitter, respectively. As depicted in Figure 340, during a first time period 302, the transmittance of s-polarized light through the polarization beamsplitter can be zero or close to zero. Similarly, as depicted in Figure 360, the reflectance of s-polarized light through the polarization beamsplitter can be maximized during the first time period 302. As mentioned above, this first time period 302 can correspond to the time when the light pulse is emitted from the laser of the LIDAR system and reflected from the polarization beamsplitter. Then, at a first transition time 304, the angle of incidence changes from a first angle of incidence to a second angle of incidence. As a result, the transmittance of s-polarized light through the polarization beamsplitter can be maximized, and the reflectance can decrease to zero or close to zero. As depicted in Figures 340 and 360, the transmittance and reflectance of s-polarized light can be maintained at these values ​​during a second time period 306. Finally, at the second transition time 308, the transmittance of the s-polarized light through the polarization beamsplitter can return to zero or near zero, and the reflectance of the s-polarized light from the polarization beamsplitter can return to its maximum value. As mentioned above, this process can be iterated as shown in Figures 340 and / or 360.

[0030] Figure 4 This is an example method 400 for a vibrating polarization beamsplitter according to one or more example embodiments of this disclosure. Figure 4In this example, computer-executable instructions of one or more modules of the LIDAR system 500 (such as the polarization beamsplitter actuation module 528) can be used to execute the example method 400. However, method 400 can also be executed without using computer-executable instructions, for example, by using a resonant circuit connected to an actuation component (such as a voice coil motor as described above).

[0031] exist Figure 4 At block 402 of method 400, the method may include emitting a first light pulse by an emitter. In some instances, the emitter may be a laser diode. While block 402 may describe the use of a single emitter, multiple emitters may be used to emit multiple light pulses simultaneously or at staggered time intervals. In some cases, different lasers may emit light pulses in different directions. Furthermore, light may be emitted as a series of pulses. The characteristics of the emitted light (such as frequency and amplitude, and other characteristics) may remain fixed in each successive light emission. For example, the frequency of light emitted from a laser may be in the range of 880-930 nm. However, these characteristics may also be variable. For example, the laser may emit light at a first amplitude at a first time and may subsequently emit light at a greater amplitude at a second time. In some embodiments, the laser may be a laser diode of a LIDAR system, wherein a vehicle LIDAR system may be used to detect objects in the vehicle's environment.

[0032] Block 404 of method 400 may include reflecting a first optical pulse by a polarization beamsplitter in a first position, wherein the polarization beamsplitter is at a first incident angle in the first position. In some embodiments, the selection of the first position of the polarization beamsplitter may be based on the type of polarized light emitted by the transmitter that the polarization beamsplitter reflects. For example, the first optical pulse may be emitted from the transmitter as s-polarized light (however, as mentioned above, emitting s-polarized light may be merely exemplary, and various other polarization states of light may also be emitted), and in such cases, the first position of the polarization beamsplitter may be selected such that the polarization beamsplitter reflects s-polarized light in the first position. For example, the first position may correspond to a first incident angle of approximately 45 degrees relative to the normal. Such reflection of s-polarized light may be desirable when an optical pulse is being emitted from a laser, as this allows the optical pulse to be reflected away from the polarization beamsplitter and into the environment. Once in the environment, the optical pulse can be reflected back from an object and return to the LIDAR system. This can allow the LIDAR system to determine information about objects in the environment of the LIDAR system, such as their distance from the LIDAR system, their size and / or shape, and other information.

[0033] Block 406 of method 400 may include adjusting the position of the polarization beamsplitter from a first position to a second position after the polarization beamsplitter reflects the first optical pulse, wherein the polarization beamsplitter is at a second incident angle in the second position. In some cases, the degree difference between the first and second incident angles may be 5 degrees or less, or more specifically, it may be a difference of about 1-2 degrees. This adjustment can be made because although the optical pulse emitted from the laser is s-polarized, the reflected light from objects in the environment of the LIDAR system may be mixed-polarized, such as s-polarized and p-polarized light. Continuing with the same example above, where s-polarized light is emitted from the transmitter, in the first position, the polarization beamsplitter can be configured to allow p-polarized light to pass through. However, as mentioned above, when the polarization beamsplitter is at the first angle, any s-polarized light can still be reflected from the polarization beamsplitter. When the optical pulse is emitted from the laser, the reflection of s-polarized light may be desirable so that the optical pulse can be reflected into the environment; however, such reflection may not be desirable for the returning light. This could be because the detector in a LiDAR system can be positioned along the return path of the light and is located behind the polarization beamsplitter from the perspective of the returning light. That is, if any returning light is reflected from the polarization beamsplitter instead of transmitted through it, then the reflected light may not reach the detector. This could be undesirable, as it would be desirable to receive as much returning light as possible at the detector in order to receive as much information as possible about the object from which the returning light is reflected.

[0034] In some embodiments, to compensate for the aforementioned potential loss of polarized return light, an adjustment of the polarization beam splitter from a first position to a second position can be performed. This adjustment can be performed, for example, using an actuator. In some instances, the actuator may include a voice coil motor. The actuator can be controlled in various ways, including using a resonant circuit (e.g., an RLC circuit), or from a computing system (e.g., regarding...). Figure 5The calculation section 505 describes the signal, etc. Adjustment can compensate for the loss of s-polarized light because, at the second incident angle, the characteristics of the polarization beamsplitter allow s-polarized light to transmit through the beamsplitter instead of being reflected from it. Therefore, when the beamsplitter is in the second position, both p-polarized and s-polarized light can transmit through the beamsplitter toward the detector, resulting in more efficient light capture by the LIDAR system. This adjustment can occur after the light pulse has been reflected from the beamsplitter and has been transmitted into the environment. In this way, when the beamsplitter is in the first position, the light pulse emitted from the laser can be reflected from the beamsplitter and enter the environment; the beamsplitter can rotate to the second position, and then the returning s-polarized and p-polarized light can transmit through the beamsplitter and reach the detector. This process can be iteratively repeated for each successive emitted light pulse from the laser, allowing the beamsplitter to effectively “oscillate” between the first and second positions. Furthermore, a relatively small degree change between the first and second incident angles can play a significant role because the polarization beamsplitter may need to oscillate fast enough between the two angles to meet the timing requirements of the LIDAR system. That is, the emitted and returned light pulses can travel at the speed of light, so the angle change may need to occur rapidly. Additionally, while the LIDAR system described herein can be described as including a single polarization beamsplitter, multiple smaller polarization beamsplitters can be used. This can be advantageous because smaller polarization beamsplitters can rotate much faster than a single polarization beamsplitter.

[0035] Block 408 of method 400 may include transmitting a returned light pulse, based on a first light pulse, through a polarization beamsplitter in a second position. In some embodiments, transmitting the returned light pulse may involve the returned light pulse traveling through the polarization beamsplitter without being reflected off onto a new path. The returned light may be transmitted through the polarization beamsplitter and enter the detector. In some embodiments, after the returned light pulse has been transmitted through the polarization beamsplitter, the polarization beamsplitter may be actuated back to the first position in anticipation of subsequent emitted light pulses being reflected into the environment. This process of alternating between the first and second positions may be performed iteratively for any number of emitted light pulses from the LIDAR system.

[0036] Block 410 of method 400 may include the detection of a returned light pulse by a detector. The detector may include, for example, a photodetector for detecting photons (returning light). Specifically, the photodetector may include an avalanche photodiode, which can operate in Geiger mode. However, other types of photodetectors may also be used for a similar purpose.

[0037] exist Figure 4The operations described and depicted in the exemplary process flow can be performed or carried out in any suitable order as desired in the various exemplary embodiments of this disclosure. Furthermore, in some exemplary embodiments, at least a portion of the operations can be performed in parallel. Additionally, in some exemplary embodiments, more operations can be performed than... Figure 4 The operations described in the text are fewer, more, or different.

[0038] Figure 4 One or more operations in the process flow can be performed by the user device, as described above, or more specifically, by one or more program modules, applications, etc., running on the device. However, it should be recognized that... Figure 4 Any operation of the process flow can be executed, at least in part, by one or more other devices in a distributed manner, or more specifically, by one or more program modules, applications, etc., executing on such devices. Furthermore, it should be recognized that processing performed in response to the execution of computer-executable instructions provided as part of an application, program module, etc., can be interchangeably described herein as being performed by the application or program module itself or by the device on which the application, program module, etc., is executing. Although Figure 4 The operation of the process can be described in the context of an exemplary vibrating polarization beam splitter, but it should be recognized that such operation can be achieved in combination with many other device configurations.

[0039] Example LIDAR system

[0040] Figure 5 An example LIDAR system 500 according to one or more embodiments of the present disclosure is illustrated. The LIDAR system 500 may represent any number of elements described herein, such as those relating to… Figure 1A The LIDAR system 100 described herein, as well as any other LIDAR system described herein, may include at least a transmitter section 501, a detector section 513, and a computation section 505. In some instances, the LIDAR system may also include a polarization beam splitter 510.

[0041] In some embodiments, the emitter portion 501 may include at least one or more emitters 502 (hereinafter referred to as "emitter" for simplicity, but multiple emitters may be equally applicable) and / or one or more optical elements 504. The emitter 502 may be a device capable of emitting light into the environment. Once the light enters the environment, it can travel toward an object 512. The light can then be reflected from the object and returned toward the LIDAR system 500, and detected by the detector portion 513 of the LIDAR system 500, which may be described below. For example, the emitter 502 may be a laser diode as described above. The emitter 502 may be capable of emitting light in a series of pulses. The optical element 504 may be an element that can be used to modify the light emitted from the emitter 502 before it enters the environment. For example, the optical element 504 may be a lens, collimator, or waveplate. In some instances, a lens may be used to focus the emitted light. A collimator may be used to collimate the emitted light. That is, a collimator may be used to reduce the divergence of the emitted light. A waveplate may be used to change the polarization state of the emitted light. Any number of different types of optical elements 504 (including optical elements not listed herein) or combinations thereof can be used in the LIDAR system 500.

[0042] In some embodiments, detector portion 513 may include at least one or more detectors 506 (hereinafter referred to as "detector" for simplicity, but multiple detectors may be equally applicable) and / or one or more optical elements 508. The detector may be a device capable of detecting reflected light from the environment (e.g., light emitted by LIDAR system 500 and reflected by object 512). For example, the detector may be a photodiode. The photodiode may specifically include an avalanche photodiode (APD), which in some instances can operate in Geiger mode. However, any other type of photodetector may also be used. The ability of detector 506 to capture reflected light from the environment can be used to allow LIDAR system 500 to determine information about object 512 in the environment. That is, LIDAR system 500 may be able to determine information such as the distance of the object from LIDAR system 500 and the shape and / or size of object 512, as well as other information. Optical element 508 may be an element for modifying the reflected light traveling toward detector 506. For example, optical element 508 may be a lens, waveplate, or filter such as a bandpass filter. In some instances, lenses may be used to focus the returned light onto detector 506. Waveplates may be used to change the polarization state of the returned light. Filters may be used to allow only light of a specific wavelength to reach the detector (e.g., the wavelength of light emitted by transmitter 502). Any number of different types of optical elements 508 (including those not listed herein) or combinations thereof may be used in the LIDAR system 500.

[0043] In some embodiments, the computing portion may include one or more processors 514 and memory 516. Processor 514 may execute instructions stored in one or more memory devices (referred to as memory 516). Instructions may be, for example, instructions for implementing functions described as being performed by one or more modules and systems disclosed above, or instructions for implementing one or more of the methods disclosed above. Processor (one or more) 514 may be implemented in, for example, a CPU, multiple CPUs, a GPU, multiple GPUs, a TPU, multiple TPUs, a multi-core processor, a combination thereof, etc. In some embodiments, processor (one or more) 514 may be arranged in a single processing device. In other embodiments, processor (one or more) 514 may be distributed across two or more processing devices (e.g., multiple CPUs; multiple GPUs; a combination thereof; etc.). A processor may be implemented as a combination of processing circuitry or computing units (such as a CPU, a GPU, or a combination of both). Therefore, for ease of illustration, a processor may refer to a single-core processor; a single processor with software multithreading capabilities; a multi-core processor; a multi-core processor with software multithreading capabilities; a multi-core processor utilizing hardware multithreading technology; a parallel processing (or computing) platform; and a parallel computing platform with distributed shared memory. Furthermore, or as another example, a processor can refer to an integrated circuit (IC), ASIC, digital signal processor (DSP), FPGA, PLC, complex programmable logic device (CPLD), discrete gate or transistor logic, discrete hardware component, or any combination thereof, designed or otherwise configured (e.g., manufactured) to perform the functions described herein.

[0044] One or more processors 514 can access memory 516 via a communication architecture (e.g., a system bus). The communication architecture can be adapted to a particular arrangement (local or distributed) and type of the processors 514. In some embodiments, the communication architecture 506 may include one or more bus architectures, such as a memory bus or memory controller; a peripheral bus; an accelerated graphics port; a processor or local bus; a combination thereof; and so on. As examples, such architectures may include an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, an Accelerated Graphics Port (AGP) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express bus, a Personal Computer Memory Card International Association (PCMCIA) bus, a Universal Serial Bus (USB), and the like.

[0045] The memory components or memory devices disclosed herein may be implemented in either volatile or non-volatile memory, or may include both volatile and non-volatile memory. Furthermore, the memory components or memory devices may be removable or non-removable, and / or located internally or externally to a computing device or component. Examples of various types of non-transitory storage media may include hard disk drives, zip drives, CD-ROMs, digital versatile optical discs (DVDs) or other optical storage devices, magnetic cassettes, magnetic tapes, disk storage devices or other magnetic storage devices, flash memory cards or other types of memory cards, cartridges, or any other non-transitory media suitable for retaining desired information and accessible by a computing device.

[0046] By way of example, non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM), which acts as an external cache memory. By way of example and not limitation, RAM is available in various forms, such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory devices or memories disclosed in the operating or computing environment described herein are intended to include one or more of these and / or any other suitable types of memory. In addition to storing executable instructions, memory 516 may also retain data.

[0047] Each LIDAR system 500 may also include a mass storage device 517 accessible by one or more processors 514 via a communication architecture 506. The mass storage device 517 may include machine-accessible instructions (e.g., computer-readable and / or computer-executable instructions). In some embodiments, the machine-accessible instructions may be encoded in the mass storage device 517 and may be arranged in a component that may be built (e.g., linked and compiled) and stored in a computer-executable form in the mass storage device 517 or in one or more other machine-accessible non-transitory storage media included in the LIDAR system 500. Such components may implement or constitute one or more of the various modules disclosed herein. Such modules are exemplified as a polarization beamsplitter actuation module 528.

[0048] The polarization beamsplitter actuation module 528, which includes computer-executable instructions, code, etc., executed by one or more of processors 514, can perform functions including, but not limited to, selectively adjusting the incident angle (first incident angle and second incident angle) of the polarization beamsplitter between at least two positions. The polarization beamsplitter actuation module 528 can also be responsible for ensuring the timing of emissions from a transmitter device (e.g., transmitter device 502) so that the vibrating polarization beamsplitter 510 can transition between a first position and a second position and back to the first position between light emissions. The synchronization of the timing can depend on several variables, such as the thermal power of transmitter 502, range aliasing considerations, etc. Furthermore, the functionality may include performing any other methods and / or processes described herein.

[0049] In some embodiments, polarization beamsplitter 510 may be the same as polarization beamsplitter 112 or any other polarization beamsplitter 510 described herein. That is, polarization beamsplitter 510 may be used to reflect light emitted from transmitter 502 and transmit (through) return light from the environment toward detector 506. As described above, the transmitter and detector configuration may be reversed such that emitted light can be transmitted through polarization beamsplitter 510 and return light can be reflected from polarization beamsplitter 510 toward detector 506.

[0050] It should also be recognized that, without departing from the scope of this disclosure, the LIDAR system 500 may include alternative and / or additional hardware, software, or firmware components beyond those described or depicted. More specifically, it should be recognized that the software, firmware, or hardware components depicted as forming part of the LIDAR system 500 are merely exemplary and some components may be absent or additional components may be provided in various embodiments. While various exemplary program modules have been depicted and described as software modules stored in a data storage device, it should be recognized that the functionality described as being supported by a program module can be implemented by any combination of hardware, software, and / or firmware. It should also be recognized that, in various embodiments, each of the modules mentioned above may represent a logical partition of the supported functionality. Such logical partitioning is depicted for ease of interpretation of the functionality and may not represent the structure of the software, hardware, and / or firmware used to implement the functionality. Thus, it should be recognized that, in various embodiments, the functionality described as being provided by a particular module may be provided at least partially by one or more other modules. Furthermore, one or more depicted modules may be absent in some embodiments, while in other embodiments, undepicted additional modules may be present and may support at least a portion of the described functionality and / or additional functionality. Furthermore, while some modules may be described and depicted as submodules of another module, in some embodiments such modules may be provided as independent modules or submodules of other modules.

[0051] While specific embodiments of this disclosure have been described, those skilled in the art will recognize that many other modifications and alternative embodiments are also within the scope of this disclosure. For example, any functionality and / or processing capabilities described with respect to a particular device or component can be performed by any other device or component. Furthermore, while various exemplary implementations and architectures have been described with respect to embodiments of this disclosure, those skilled in the art will recognize that many other modifications to the exemplary implementations and architectures described herein are also within the scope of this disclosure.

[0052] The foregoing description of block diagrams and flowcharts of systems, methods, apparatuses, and / or computer program products according to exemplary embodiments has described certain aspects of this disclosure. It should be understood that one or more blocks in the block diagrams and flowcharts, as well as combinations of blocks in the block diagrams and flowcharts, can be implemented by the execution of computer-executable program instructions. Similarly, according to some embodiments, some blocks in the block diagrams and flowcharts may not necessarily need to be executed in the order presented, or may not need to be executed at all. Furthermore, in some embodiments, additional components and / or operations beyond those depicted in the blocks of the block diagrams and / or flowcharts may be present.

[0053] Therefore, the blocks in block diagrams and flowcharts support combinations of components for performing a specified function, combinations of elements or steps for performing a specified function, and program instruction components for performing a specified function. It should also be understood that each block in a block diagram and flowchart, and combinations of blocks in block diagrams and flowcharts, can be implemented by a dedicated, hardware-based computer system, or a combination of dedicated hardware and computer instructions, for performing the specified function, element, or step.

[0054] The contents described herein in this specification and accompanying drawings include examples of systems, devices, technologies, and computer program products that, individually and in combination, allow for the automated provision of vehicle profile updates. It is certainly impossible to describe every conceivable combination of components and / or methods for the purpose of describing the various elements of this disclosure, but it will be appreciated that many further combinations and arrangements of the disclosed elements are possible. Therefore, it will be apparent that various modifications can be made to this disclosure without departing from its scope or spirit. Furthermore, or alternatively, other embodiments of this disclosure may become apparent from consideration of the specification and accompanying drawings and from the practice of this disclosure as presented herein. The examples presented in the specification and accompanying drawings are intended in all respects to be illustrative rather than limiting. While specific terminology is used herein, it is used only in a general and descriptive sense and not for limiting purposes.

[0055] As used herein, the terms “environment,” “system,” “unit,” “module,” “architecture,” “interface,” “component,” etc., refer to entities related to a computer or to an operating device having one or more defined functions. The terms “environment,” “system,” “module,” “component,” “architecture,” “interface,” and “unit” are used interchangeably and can collectively refer to functional elements. Such entities can be hardware, a combination of hardware and software, software, or software in execution. As an example, a module can be implemented in a process running on a processor, a processor, an object, an executable portion of software, a thread of execution, a program, and / or a computing device. As another example, both a software application executing on a computing device and the computing device can implement a module. As yet another example, one or more modules can reside within a process and / or a thread of execution. A module can reside on a single computing device or be distributed across two or more computing devices. As disclosed herein, a module can be executed from various computer-readable non-transitory storage media on which various data structures are stored. Modules can communicate via local and / or remote processes based on signals (analog or digital) having one or more data packets (e.g., data from a component interacting with a local system, another component in a distributed system, and / or interacting with other systems across a network (such as a wide area network) via signals).

[0056] As another example, the module can be implemented in or may include a device having defined functions provided by mechanical parts, which are operated by electrical or electronic circuitry controlled by a software or firmware application executed by a processor. Such a processor may be internal or external to the device and may execute at least a portion of the software or firmware application. In another example, the module can be implemented in or may include a device that provides defined functions through electronic components without mechanical parts. The electronic components may include a processor to execute software or firmware that at least partially allows or otherwise facilitates the functionality of the electronic components.

[0057] In some embodiments, modules may communicate via local and / or remote processes based on signals (analog or digital) having one or more data packets (e.g., data from one component interacting with a local system, another component in a distributed system, and / or interacting with other systems across a network (such as a wide area network) via signals). Additionally, or in other embodiments, modules may communicate or be otherwise coupled via thermal, mechanical, electrical, and / or electromechanical coupling mechanisms (such as conduits, connectors, combinations thereof). The interface may include input / output (I / O) components and associated processors, applications, and / or other programming components.

[0058] Furthermore, in this specification and accompanying drawings, terms such as “repository,” “storage device,” “data repository,” “data storage device,” “memory,” “storage,” and substantially any other information storage component relating to the operation and function of the components of this disclosure refer to a memory component, an entity implemented in one or more memory devices, or a component forming a memory device. It should be noted that the memory components or memory devices described herein implement or include non-transitory computer storage media that are readable or otherwise accessible by a computing device. Such media may be implemented using any method or technique for storing information such as machine-accessible instructions (e.g., computer-readable instructions), information structures, program modules, or other information objects.

[0059] Conditional language (such as, in particular, "can," "may," "will," or "may") is generally intended to convey, unless otherwise specifically indicated or otherwise understood in the context in which it is used, that certain implementations may include certain features, elements, and / or operations that are not included in other implementations. Therefore, such conditional language is not generally intended to imply that features, elements, and / or operations are necessary in any way for one or more implementations, or that one or more implementations necessarily include logic for determining whether such features, elements, and / or operations are included in or will be performed in any particular implementation, with or without user input or prompting.

Claims

1. A system comprising: The transmitter is configured to emit a first light pulse; The detector is configured to receive a returned optical pulse, the returned optical pulse comprising a reflection of a first optical pulse; A polarization beam splitter having a first position and a second position, wherein the polarization beam splitter reflects a first optical pulse at the first position and transmits the returned optical pulse at the second position; as well as The actuator selectively moves the polarization beam splitter between a first position and a second position. The frequency at which the polarization beam splitter rotates between the first position and the second position corresponds to the frequency of the light emitted by the transmitter.

2. The system of claim 1, wherein the actuator is configured to move the polarization beamsplitter from a first position to a second position after the transmitter emits the first optical pulse and before the returned optical pulse is transmitted by the polarization beamsplitter.

3. The system of claim 1, wherein the actuator is configured to move the polarization beamsplitter from the second position to the first position after the returned optical pulse is transmitted by the polarization beamsplitter and before the transmitter emits the second optical pulse.

4. The system of claim 1, wherein the actuator comprises at least one of a voice coil motor or a non-vibrating motor.

5. The system of claim 1, wherein the first optical pulse is in a first polarization state, wherein the returned optical pulse comprises light in the first polarization state and light in a second polarization state, and wherein the polarization beam splitter is configured to transmit at least a portion of both the light in the first polarization state and the light in the second polarization state.

6. The system of claim 5, wherein at least 90% of the light in the first polarization state and the light in the second polarization state are transmitted by a polarization beam splitter in the second position.

7. The system of claim 1, wherein the difference between the first position and the second position is less than 5 degrees.

8. The system of claim 1, wherein the first position corresponds to an incident angle of approximately 45 degrees and the second position corresponds to an incident angle of approximately 43.5 degrees.

9. A method comprising: The transmitter emits the first light pulse; The first optical pulse is reflected by a polarization beamsplitter in a first position, wherein the polarization beamsplitter is at a first incident angle in the first position; After the polarization beam splitter reflects the first optical pulse, the position of the polarization beam splitter is adjusted from the first position to the second position, wherein the polarization beam splitter is at the second incident angle in the second position; The returning optical pulse is transmitted through the polarization beamsplitter in the second position, and the returning optical pulse is based on the first optical pulse. as well as The returned light pulse is detected by the detector. The frequency at which the polarization beam splitter rotates between the first position and the second position corresponds to the frequency of the light emitted by the transmitter.

10. The method of claim 9, wherein adjusting the incident angle to the second incident angle occurs after the transmitter emits the first optical pulse and before the returned optical pulse is received at the polarization beam splitter.

11. The method of claim 9, further comprising: After receiving the returned optical pulse, the polarization beam splitter is adjusted from the second position to the first position.

12. The method of claim 9, wherein adjusting the angle of incidence comprises using at least one of a voice coil motor or a non-vibrating motor to adjust the angle of incidence.

13. The method of claim 9, wherein the first optical pulse is in a first polarization state, and wherein the returned optical pulse comprises light in the first polarization state and light in a second polarization state, and wherein the polarization beam splitter is configured to transmit at least a portion of both the light in the first polarization state and the light in the second polarization state.

14. The method of claim 13, wherein at least 90% of the light in the first polarization state and the light in the second polarization state are transmitted by the polarization beam splitter in the second position.

15. The method of claim 9, wherein the difference between the first position and the second position is less than 5 degrees.

16. The method of claim 9, wherein the first angle of incidence is approximately 45 degrees and the second angle of incidence is approximately 43.5 degrees.

17. A non-transitory computer-readable medium comprising computer-executable instructions stored thereon, the computer-executable instructions causing the one or more processors to perform the following operations when executed by one or more processors: The position of the polarization beam splitter is adjusted to a first position, wherein the polarization beam splitter is at a first incident angle relative to the path of the light emitted by the transmitter in the first position; The transmitter emits a first optical pulse in a path pointing towards the polarization beam splitter; After the polarization beam splitter reflects the first optical pulse, the position of the polarization beam splitter is adjusted from the first position to the second position, wherein the polarization beam splitter is at the second incident angle in the second position; as well as The detector receives a return optical pulse based on the first optical pulse, which is then transmitted by a polarization beam splitter at a second position. The frequency at which the polarization beam splitter rotates between the first position and the second position corresponds to the frequency of the light emitted by the transmitter.

18. The non-transitory computer-readable medium of claim 17, wherein the difference between the first incident angle and the second incident angle is five degrees or less.

19. The non-transitory computer-readable medium of claim 17, wherein the incident angle is adjusted to a second incident angle after the transmitter emits the first optical pulse and before the returned optical pulse is received at the polarization beam splitter.

20. The non-transitory computer-readable medium of claim 17, wherein the computer-executable instructions further cause the one or more processors to: After receiving the returned optical pulse, the polarization beam splitter is adjusted from the second position to the first position.

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