Run a cross-bench experiment

A measurement across two bench PCs, from one console: the half-wave plate is on this bench, the spectrometer on another, and the experiment turns the one while reading the other. This page takes it from two installed benches to a finished run with its analysis and report — with plesty-pol-pl, the polarisation-resolved photoluminescence experiment, in its demo configuration.

	Local bench	spec-pc
Role	master — its console shows and drives both	node — serves its own devices
Runs	the console, the experiment pol-pl, the stage hwp (plesty-k10cr1)	the spectrometer spec (plesty-lightfield-spectrometer)
Reached at	—	its agent, <spec-pc>:5560

The demo is a real run of the experiment: the stage is the released module in its simulator, and the spectrometer is a fixed commit of the demo/pol-pl branch of its module, which answers with spectra really measured on sample E098-SIL — quantum dot QD-002, the half-wave plate turned from 0° to 178° in 2° steps. The experiment cannot tell the difference, and neither can the analysis.

The images on this page were taken with both benches on one computer, so spec-pc’s address is 127.0.0.1:5560 and both see /tmp as the shared disk. In a lab, spec-pc has an address of its own and the shared disk is a network folder.

What you need

• PLESTY Bench on both PCs — see Install.

• A shared data disk: one folder both PCs can write to, each under its own path (/mnt/plesty on one, D:\plesty on another). Runs are written there, so the spectrometer on spec-pc writes its spectra straight into the run. For the demo spectrometer it must be the folder its --replay-run-root names without the pol-pl at the end — /tmp as shipped.

• The network between them, with spec-pc’s port 5560 reachable from the local bench.

1. Prepare spec-pc

On spec-pc:

1. Hub ▸ Browse…, find plesty-lightfield-spectrometer, choose Repository (git) at ref demo/pol-pl, and Install module.

2. Server ▸ Configure…: press Generate for a token and Copy it — you will paste it on the local bench. Save.

3. Server ▸ Start agent. The status line now says where the agent listens.

Nothing else: the local bench will ask spec-pc to start the spectrometer when the run needs it.

2. Make the local bench the master

On the local bench:

1. Server ▸ Configure…: set Role to master, and Save.

   

2. Server ▸ Benches…: Add a row — Name spec-pc, Address its address and port 5560, Token the one you copied — and Save.

   

The Devices tab now shows spec-pc’s spectrometer, with spec-pc under Host:

3. Install the experiment and create a run

1. Hub ▸ Browse…, find plesty-pol-pl, choose Repository (git) and Install module.

2. On the Experiments tab, press Create . Choose pol-pl and, as Config, config/demo.yaml — the sweep the demo spectrometer holds. Create.

   

4. Tell the experiment where its instruments are

Select the run, press Configure and open Device Setup.

1. Under Benches, Add a row for spec-pc: its Address and Token, and its Shared data — where spec-pc sees the shared disk. On the first row, this machine’s Shared data — where it sees the same disk.

2. In the spec group, set Host to spec-pc. hwp stays on bench-local, this machine.

3. Save.

The values go into the module’s .env, and only the names of the variables holding them into its setup.yaml — see The benches and the shared disk.

5. Run it

Press Run and switch to the Visualization pane.

What happens, in order:

1. The shared disk is checked. This bench writes a small file under its Shared data; spec-pc reads it under its own and answers. If the two see different folders, the run stops here and names spec-pc.

2. Each instrument is started on its bench: hwp here, and spec on spec-pc through its agent. A small window names each while it opens.

3. The run measures: 90 angles, a spectrum at each. The views fill as it goes — the latest Spectrum, the Spectral map of all of them against the angle, and the Fine structure: each line’s position against the angle, with the sine fitted to it.

4. It analyses and reports. When the last angle is in, the fine-structure analysis runs and the run writes report.html into its folder. Then both instruments are stopped again, each on its bench.

The demo takes about a minute. While it runs, the Devices tab shows both instruments, one on each bench:

6. Read the result

The completed run’s Visualization shows the four emission lines of QD-002. Two of them swing against the angle — their energy follows the polarisation — and two stay flat:

That swing is the fine-structure splitting (FSS): the peak-to-peak energy difference between a line’s two polarisation components. The analysis reports, for this run:

Line	Splitting	Polarisation axis
778.140 nm	11.52 ± 0.13 µeV	72.8°
780.143 nm	11.42 ± 0.21 µeV	27.7°
780.068 nm, 780.581 nm	not resolved (below 3 standard errors)	—

The report

The run wrote report.html into its folder when it ended — Open run opens the folder, and Export HTML in the Report pane saves a copy anywhere. It needs nothing but a browser, and holds the whole run:

Device setup records where each instrument ran — the bench, the address the run reached it at, and where that bench sees the shared disk:

Fine structure of QD-002 is the analysis as it reports itself: its options, its conclusion, the splitting per line, and each line’s position against the half-wave-plate angle with its fitted sine:

Next

• The same with your own instruments: Run an experiment explains every step in full.

• Watching and driving spec-pc’s devices from here, beyond runs: Several benches.

• How the run starts devices across benches and checks the disk: Experiment runs.