SHFPPC Sweeper¶
The SHFPPC Sweeper is a feature that allows users to perform multi-dimensional sweeps effectively by externally triggering parameter sweeps instead of uploading parameters in each sweep step. It is only accessible via LabOne Q and the LabOne Python API.
Features¶
- Triggered multi-dimensional sweep
Description¶
The SHFPPC Sweeper uses a uploaded JSON file to define all sweep parameters, and then configures the instrument with the according sweep parameters after receiving external triggers to perform multi-dimensional sweeps. The related nodes are listed in the Device Node Tree.
JSON File¶
The JSON file consists of four sections as shown in the table below.
| JSON String Session | Setting | Description |
|---|---|---|
| "header" | "version": "1.0" | Sets JSON format version. The valid version is 1.0. |
| "dimensions" | "pump_on", "pump_frequency", "pump_power", "probe_on", "probe_frequency", "probe_power", "cancellation_on", "cancellation_phase", "cancellation_attenuation" | Sets sweep dimensions. |
| "flat_list" | A series of arrays | Sets a flat list of sweep data using a series of arrays. Each array represents one step of the sweep and includes a number of values which match the configuration of the "dimensions". The maximum number of arrays is 100000. |
| "repetitions" | Integer (>0) | Sets a number of repetitions of the "flat_list". This setting is optional, and the default value is 1. |
The example below shows how the JSON file defines multi-dimensional sweeps. In the example, a 3-dimensional sweep is defined, and each sweep step sets 3 values to pump frequency, pump power and probe frequency, respectively. The sweep goes through the 9 sweep steps from the top to the bottom, and is then repeated 10 times.
{
"header": {
"version": "1.0"
},
"dimensions": [
"pump_frequency",
"pump_power",
"probe_frequency"
],
"flat_list": [
[6.00e9, 1.0, 5.00e9],
[6.01e9, 1.0, 5.00e9],
[6.02e9, 1.0, 5.00e9],
[6.00e9, 1.2, 5.18e9],
[6.01e9, 1.2, 5.18e9],
[6.02e9, 1.2, 5.18e9],
[6.00e9, 1.4, 5.43e9],
[6.01e9, 1.4, 5.43e9],
[6.02e9, 1.4, 5.43e9]
],
"repetitions": 10
}
Run the Sweeper¶
The Sweeper can be enabled after uploading a valid JSON file. Then, the data in each array in the "flat_list" section of the JSON file is used in sequence to configure the instrument on each trigger pulse received on the respective physical Trigger Input port. Trigger Input port N is only used for the Sweeper module of SHFPPC channel N. For the SHFPPC2, Trigger Inputs 1 and 2 are used; Trigger Inputs 3 and 4 are non-functional.
To properly trigger the SHFPPC, the width of the trigger pulse should be at least 25 ms, and the number of triggers should at least be the product of the number of arrays (i.e. sweep steps) in the "flat_list" section and the number of repetitions.
The sweep status can be monitored while the Sweeper is running; see details in the Device Node Tree.