WEBVTT NOTE This file was exported by MacCaption version 7.0.13 to comply with the WebVTT specification dated March 27, 2017. 00:00:00.200 --> 00:00:02.970 align:center line:-1 position:50% size:48% Hi, and welcome to the next module on quantum sensing. 00:00:02.970 --> 00:00:07.474 align:center line:-1 position:50% size:56% In this module, we will look at applications of quantum radar, quantum lidar, 00:00:07.474 --> 00:00:12.646 align:center line:-1 position:50% size:54% and how to implement a TDC application on the FPGA of a digitizer. 00:00:12.646 --> 00:00:13.981 align:center line:-1 position:50% size:23% Let's get started. 00:00:13.981 --> 00:00:16.617 align:center line:-1 position:50% size:41% A quantum sensing application called quantum elimination 00:00:16.617 --> 00:00:20.153 align:center line:-1 position:50% size:37% plays an important role for new radar technologies. 00:00:20.153 --> 00:00:23.590 align:center line:-1 position:50% size:47% This research has gained attention due to the possible improvements 00:00:23.590 --> 00:00:27.694 align:center line:-1 position:50% size:42% to sensitivity of radar and other target detection technologies. 00:00:27.694 --> 00:00:30.697 align:center line:-1 position:50% size:42% The approach takes advantage of strong signal correlations 00:00:30.697 --> 00:00:33.700 align:center line:-1 position:50% size:35% that can be created in electromagnetic beams 00:00:33.700 --> 00:00:35.469 align:center line:-1 position:50% size:36% using quantum processes. 00:00:35.469 --> 00:00:39.072 align:center line:-1 position:50% size:49% These quantum correlations are a form of quantum entanglement 00:00:39.072 --> 00:00:41.909 align:center line:-1 position:50% size:57% giving advantage to the detection process. 00:00:41.909 --> 00:00:44.945 align:center line:-1 position:50% size:41% To get a higher range in sensitivity of stealth objects, 00:00:44.945 --> 00:00:47.481 align:center line:-1 position:50% size:32% we would look at strong quantum correlations. 00:00:47.481 --> 00:00:50.918 align:center line:-1 position:50% size:48% The path to detect unknown objects through air requires a method 00:00:50.918 --> 00:00:53.153 align:center line:-1 position:50% size:43% known as two-mode squeezing. 00:00:53.153 --> 00:00:56.757 align:center line:-1 position:50% size:37% An entanglement source emits two frequency beams 00:00:56.757 --> 00:00:59.293 align:center line:-1 position:50% size:37% called a signal and an idler. 00:00:59.293 --> 00:01:02.963 align:center line:-1 position:50% size:39% The entanglement then helps with the signal-to-noise ratio 00:01:02.963 --> 00:01:06.600 align:center line:-1 position:50% size:34% via the correlations inherent in entanglement. 00:01:06.600 --> 00:01:11.204 align:center line:-1 position:50% size:47% The idler is immediately measured, then kept at some base station, 00:01:11.204 --> 00:01:16.710 align:center line:-1 position:50% size:47% while the signal is sent to a probe toward the unknown stealth object. 00:01:16.710 --> 00:01:18.679 align:center line:-1 position:50% size:29% The receiving signals from the environment 00:01:18.679 --> 00:01:20.814 align:center line:-1 position:50% size:39% both pass through a receiver. 00:01:20.814 --> 00:01:26.053 align:center line:-1 position:50% size:47% The two signals are then compared or read for post processing. 00:01:26.053 --> 00:01:29.022 align:center line:-1 position:50% size:38% There's a lot of hype around this topic of quantum radar. 00:01:29.022 --> 00:01:30.891 align:center line:-1 position:50% size:27% To add a disclaimer, 00:01:30.891 --> 00:01:33.427 align:center line:-1 position:50% size:29% this research field still requires a lot of work 00:01:33.427 --> 00:01:39.833 align:center line:-1 position:50% size:47% to prove that quantum radar is still more sensitive than classical radar. 00:01:39.833 --> 00:01:42.235 align:center line:-1 position:50% size:38% There's work being done at the University of Waterloo 00:01:42.235 --> 00:01:44.938 align:center line:-1 position:50% size:48% in research of quantum illumination. 00:01:44.938 --> 00:01:47.140 align:center line:-1 position:50% size:32% On the left, you will see two-mode squeezing 00:01:47.140 --> 00:01:51.878 align:center line:-1 position:50% size:53% created in the two entanglement beams as input into a radar system. 00:01:51.878 --> 00:01:55.215 align:center line:-1 position:50% size:46% Quantum illumination seems to be very robust to the presence 00:01:55.215 --> 00:01:57.417 align:center line:-1 position:50% size:40% of background noise and loss, 00:01:57.417 --> 00:01:59.987 align:center line:-1 position:50% size:56% suggesting broader practical applications. 00:01:59.987 --> 00:02:01.355 align:center line:-1 position:50% size:22% In this research, 00:02:01.355 --> 00:02:04.992 align:center line:-1 position:50% size:48% they demonstrated proof of concept to quantum enhancement 00:02:04.992 --> 00:02:08.428 align:center line:-1 position:50% size:47% in the detected signal-to-noise ratio of an order of magnitude 00:02:08.428 --> 00:02:11.832 align:center line:-1 position:50% size:45% when comparing the performance of an entangled photon source 00:02:11.832 --> 00:02:18.505 align:center line:-1 position:50% size:59% to an ideal classical noise source that saturates the classical bound for correlation. 00:02:18.505 --> 00:02:23.643 align:center line:-1 position:50% size:49% You can see that it involves the use of a Josephson parametric amplifier, 00:02:23.643 --> 00:02:27.214 align:center line:-1 position:50% size:44% used as a microwave parametric downconversion source, 00:02:27.214 --> 00:02:30.417 align:center line:-1 position:50% size:40% along with classical amplifiers to measure the quadratures 00:02:30.417 --> 00:02:32.386 align:center line:-1 position:50% size:30% of the signal and idler. 00:02:32.386 --> 00:02:35.422 align:center line:-1 position:50% size:43% In this case, they measured the frequency modes of the JPA 00:02:35.422 --> 00:02:37.858 align:center line:-1 position:50% size:30% between 4 and 8 GHz. 00:02:37.858 --> 00:02:42.462 align:center line:-1 position:50% size:46% The quantumness is characterized as a function of the output power, 00:02:42.462 --> 00:02:44.664 align:center line:-1 position:50% size:40% shown in the figure to the left. 00:02:44.664 --> 00:02:48.268 align:center line:-1 position:50% size:39% This figure demonstrates an Eigenvalue of less than 1, 00:02:48.268 --> 00:02:50.604 align:center line:-1 position:50% size:44% implying that they are entangled, 00:02:50.604 --> 00:02:55.175 align:center line:-1 position:50% size:42% as described by the test within the group of Chang et al. 00:02:55.175 --> 00:02:57.344 align:center line:-1 position:50% size:48% On the right is the same experiment 00:02:57.344 --> 00:02:59.913 align:center line:-1 position:50% size:49% but a more detailed schematic setup 00:02:59.913 --> 00:03:03.016 align:center line:-1 position:50% size:49% from the group at the Institute of Quantum Computing. 00:03:03.016 --> 00:03:05.218 align:center line:-1 position:50% size:40% At the heart is the amplified quantum source 00:03:05.218 --> 00:03:07.320 align:center line:-1 position:50% size:41% to generate the entanglement. 00:03:07.320 --> 00:03:10.223 align:center line:-1 position:50% size:37% This device sits in a dilution refrigerator at 4 K, 00:03:10.223 --> 00:03:13.760 align:center line:-1 position:50% size:41% which limits how these devices can be used in the real world. 00:03:13.760 --> 00:03:18.965 align:center line:-1 position:50% size:59% For example, an ideal quantum radar device would be done at room temperature. 00:03:18.965 --> 00:03:21.368 align:center line:-1 position:50% size:30% But there's still work that needs to be done 00:03:21.368 --> 00:03:24.271 align:center line:-1 position:50% size:35% for this research to bring it into the real world 00:03:24.271 --> 00:03:26.606 align:center line:-1 position:50% size:45% outside of the cryogenic chamber. 00:03:26.606 --> 00:03:29.643 align:center line:-1 position:50% size:47% This is the beginning of a new area that could affect, say, 00:03:29.643 --> 00:03:31.945 align:center line:-1 position:50% size:51% the aerospace and defense industries. 00:03:31.945 --> 00:03:35.148 align:center line:-1 position:50% size:40% The other topic in this module is quantum lidar. 00:03:35.148 --> 00:03:38.819 align:center line:-1 position:50% size:41% Lidar, which is an acronym for light detection and ranging, 00:03:38.819 --> 00:03:43.123 align:center line:-1 position:50% size:50% is a remote sensing method that uses light in the form of pulsed lasers 00:03:43.123 --> 00:03:44.791 align:center line:-1 position:50% size:26% to measure ranges. 00:03:44.791 --> 00:03:48.161 align:center line:-1 position:50% size:55% Quantum lidar has many advantages over some of the classical radar systems 00:03:48.161 --> 00:03:49.729 align:center line:-1 position:50% size:27% that are used today. 00:03:49.729 --> 00:03:53.767 align:center line:-1 position:50% size:48% When compared to classical radar, which uses pulsed RF for detection, 00:03:53.767 --> 00:03:57.104 align:center line:-1 position:50% size:35% lidar uses pulsed photons to generate precise, 00:03:57.104 --> 00:04:00.040 align:center line:-1 position:50% size:40% three-dimensional information about the shape of objects 00:04:00.040 --> 00:04:02.442 align:center line:-1 position:50% size:44% and their surface characteristics. 00:04:02.442 --> 00:04:05.679 align:center line:-1 position:50% size:47% Another improvement that lidar has is its sensitivity. 00:04:05.679 --> 00:04:09.149 align:center line:-1 position:50% size:51% This is because of the squeezed-state quantum effects that make for 00:04:09.149 --> 00:04:12.486 align:center line:-1 position:50% size:40% better resolution, strong anti-interference ability, 00:04:12.486 --> 00:04:15.255 align:center line:-1 position:50% size:43% and good low-altitude detection. 00:04:15.255 --> 00:04:17.557 align:center line:-1 position:50% size:36% A lidar experiment consists of these core components: 00:04:17.557 --> 00:04:20.293 align:center line:-1 position:50% size:36% a pulsed laser to generate optical pulses, 00:04:20.293 --> 00:04:22.195 align:center line:-1 position:50% size:47% lenses to collect scattered photons, 00:04:22.195 --> 00:04:25.732 align:center line:-1 position:50% size:45% a single photon-sensitive detector like a photomultiplier tube 00:04:25.732 --> 00:04:28.068 align:center line:-1 position:50% size:38% or an avalanche photodiode, 00:04:28.068 --> 00:04:31.838 align:center line:-1 position:50% size:53% and processing electronics for timestamping and counting photons. 00:04:31.838 --> 00:04:33.940 align:center line:-1 position:50% size:39% Here is what that experiment might look like 00:04:33.940 --> 00:04:36.209 align:center line:-1 position:50% size:51% to transmit and receive these photons 00:04:36.209 --> 00:04:39.913 align:center line:-1 position:50% size:39% after they interact with an object in the environment. 00:04:39.913 --> 00:04:44.851 align:center line:-1 position:50% size:49% The hardware that is used here demonstrates a TDC implementation 00:04:44.851 --> 00:04:49.356 align:center line:-1 position:50% size:33% on a PXI digitizer with custom FPGA code. 00:04:49.356 --> 00:04:52.792 align:center line:-1 position:50% size:43% PathWave FPGA is software that gives us access to program 00:04:52.792 --> 00:04:57.397 align:center line:-1 position:50% size:42% the open FPGA sandbox region of the M3102A digitizer. 00:04:57.397 --> 00:04:58.632 align:center line:-1 position:50% size:30% Through this software, 00:04:58.632 --> 00:05:02.936 align:center line:-1 position:50% size:48% we can customize our FPGA design from a graphical user interface. 00:05:02.936 --> 00:05:08.308 align:center line:-1 position:50% size:59% Our custom FPGA design was implemented and was created from a combination 00:05:08.308 --> 00:05:14.181 align:center line:-1 position:50% size:53% of standard PathWave FPGA IP blocks, Vivado IP blocks, and VHDL blocks. 00:05:14.181 --> 00:05:17.617 align:center line:-1 position:50% size:43% These blocks are wired together and completed into a bitfile 00:05:17.617 --> 00:05:20.420 align:center line:-1 position:50% size:43% using the PathWave FPGA GUI. 00:05:20.420 --> 00:05:23.223 align:center line:-1 position:50% size:44% The basic idea behind implementing the pulse counting 00:05:23.223 --> 00:05:26.159 align:center line:-1 position:50% size:35% on a digitizer is as follows. 00:05:26.159 --> 00:05:28.929 align:center line:-1 position:50% size:43% First, we set a voltage threshold that allows us to determine 00:05:28.929 --> 00:05:30.864 align:center line:-1 position:50% size:38% when a pulsed edge occurs. 00:05:30.864 --> 00:05:34.034 align:center line:-1 position:50% size:41% The frequency at which the capture pulses is based on 00:05:34.034 --> 00:05:37.571 align:center line:-1 position:50% size:39% is the clock rate of the FPGA within the digitizer. 00:05:37.571 --> 00:05:42.709 align:center line:-1 position:50% size:42% In this case, our demonstration, the clock rate is 100 MHz. 00:05:42.709 --> 00:05:45.979 align:center line:-1 position:50% size:35% This means we can count 1 pulse per 10 ns. 00:05:45.979 --> 00:05:50.483 align:center line:-1 position:50% size:46% For time tagging, we can increase the time resolution beyond 10 ns. 00:05:50.483 --> 00:05:51.918 align:center line:-1 position:50% size:44% We can achieve this in two parts. 00:05:51.918 --> 00:05:55.555 align:center line:-1 position:50% size:39% First, the FPGA oversamples the data by five, 00:05:55.555 --> 00:05:59.859 align:center line:-1 position:50% size:37% effectively leading to a 500 MSa/s sampling rate. 00:05:59.859 --> 00:06:02.862 align:center line:-1 position:50% size:55% This gives us 2 ns between each sample. 00:06:02.862 --> 00:06:07.067 align:center line:-1 position:50% size:44% Secondly, the linear interpolation is implemented based on 00:06:07.067 --> 00:06:10.170 align:center line:-1 position:50% size:46% the user-defined voltage threshold and the sample voltage 00:06:10.170 --> 00:06:12.672 align:center line:-1 position:50% size:53% before and after the threshold crossing. 00:06:12.672 --> 00:06:14.975 align:center line:-1 position:50% size:45% This improves our time resolution significantly, 00:06:14.975 --> 00:06:19.012 align:center line:-1 position:50% size:45% based on the properties of the time-interpolator algorithm. 00:06:19.012 --> 00:06:20.647 align:center line:-1 position:50% size:41% Here's our experimental setup. 00:06:20.647 --> 00:06:21.815 align:center line:-1 position:50% size:22% It's quite simple. 00:06:21.815 --> 00:06:25.485 align:center line:-1 position:50% size:50% There's channel 1 of an M3201A AWG 00:06:25.485 --> 00:06:29.990 align:center line:-1 position:50% size:40% that is connected to channel 2 of the M3102A digitizer. 00:06:29.990 --> 00:06:32.859 align:center line:-1 position:50% size:32% The AWG generates a train of square pulses 00:06:32.859 --> 00:06:37.097 align:center line:-1 position:50% size:45% to simulate what you may receive from a photon detector. 00:06:37.097 --> 00:06:41.901 align:center line:-1 position:50% size:36% The digitizer is loaded with our custom TDC bitfile 00:06:41.901 --> 00:06:44.537 align:center line:-1 position:50% size:42% generated by PathWave FPGA. 00:06:44.537 --> 00:06:48.475 align:center line:-1 position:50% size:47% A simplified version of the FPGA design is shown here. 00:06:48.475 --> 00:06:51.745 align:center line:-1 position:50% size:33% Analog data from channel 2 of the digitizer 00:06:51.745 --> 00:06:54.514 align:center line:-1 position:50% size:31% is sent down two paths of the sandbox. 00:06:54.514 --> 00:06:56.016 align:center line:-1 position:50% size:21% In the first path, 00:06:56.016 --> 00:06:58.184 align:center line:-1 position:50% size:34% the data is sent to the data acquisition block 00:06:58.184 --> 00:06:59.419 align:center line:-1 position:50% size:36% associated with channel 2, 00:06:59.419 --> 00:07:03.623 align:center line:-1 position:50% size:40% just as it would be in a standard digitizer design. 00:07:03.623 --> 00:07:05.125 align:center line:-1 position:50% size:26% In the second path, 00:07:05.125 --> 00:07:07.661 align:center line:-1 position:50% size:31% the data is sent to the custom TDC block. 00:07:07.661 --> 00:07:10.330 align:center line:-1 position:50% size:44% The block implements pulse counting and timestamping 00:07:10.330 --> 00:07:12.265 align:center line:-1 position:50% size:29% of the channel 2 data. 00:07:12.265 --> 00:07:16.036 align:center line:-1 position:50% size:51% The TDC settings are configured from an FPGA memory-mapped block 00:07:16.036 --> 00:07:19.039 align:center line:-1 position:50% size:51% that is accessible through Python API. 00:07:19.039 --> 00:07:23.943 align:center line:-1 position:50% size:47% The output of the TDC is then routed to the data acquisition block 00:07:23.943 --> 00:07:26.780 align:center line:-1 position:50% size:40% typically associated with channel 1 of the digitizer. 00:07:26.780 --> 00:07:29.716 align:center line:-1 position:50% size:51% By using both data acquisition blocks, 00:07:29.716 --> 00:07:35.322 align:center line:-1 position:50% size:53% we can read the standard analog input data and the TDC simultaneously. 00:07:35.322 --> 00:07:38.591 align:center line:-1 position:50% size:50% This wraps it up for our lesson on quantum radar and quantum lidar. 00:07:38.591 --> 00:07:41.761 align:center line:-1 position:50% size:46% Quantum radar and quantum lidar are very much on the horizon 00:07:41.761 --> 00:07:44.597 align:center line:-1 position:50% size:32% and have the probability to change the industry 00:07:44.597 --> 00:07:46.599 align:center line:-1 position:50% size:42% for classical radar applications. 00:07:46.599 --> 00:07:48.201 align:center line:-1 position:50% size:51% Thank you for listening to this module. 00:07:48.201 --> 00:07:49.469 align:center line:-1 position:50% size:36% I'll see you at the next one.