> ## Documentation Index
> Fetch the complete documentation index at: https://docs.atomscale.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Photoluminescence

> Spectral analysis of photoluminescence emission measurements

Photoluminescence (PL) analysis processes spectroscopy files, automatically extracts acquisition metadata from filenames, and normalizes emission intensity by power, exposure, and accumulation parameters. This makes spectra from different measurement conditions directly comparable.

## Overview

The PL pipeline processes data in three stages:

1. **File parsing**: reads energy and intensity columns from uploaded CSV spectroscopy files
2. **Metadata extraction**: an LLM parses the filename to recover sample identity, measurement location, laser power, exposure time, accumulation count, and energy range
3. **Intensity normalization**: divides raw intensity by the product of power, exposure, and accumulation so that spectra taken under different conditions can be compared on equal footing

### Key Metrics

| Metric    | What It Tells You                                                                                                                                       |
| --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Energy    | Spectral position of emission features, in the units recorded by the instrument (typically eV or nm).                                                   |
| Intensity | Emission strength. When metadata is complete, intensity is normalized by acquisition parameters. When metadata is incomplete, raw counts are preserved. |

<Tabs>
  <Tab title="Guide">
    ### Adding Data

    Upload CSV spectroscopy files through the data page. Each file should contain two columns: energy and intensity. Processing starts automatically once the upload completes.

    The pipeline extracts metadata (sample ID, measurement location, laser power, exposure, accumulation) from the filename. Including these details in the filename enables automatic intensity normalization.

    ### Viewing Results

    Once processing completes, the workspace displays a spectrum chart plotting energy vs. intensity. A status badge indicates pipeline progress.

    <Note>
      If the filename does not contain enough metadata to determine power, exposure, and accumulation values, the spectrum displays raw (unnormalized) intensity. The normalization flag in the results indicates whether normalization was applied.
    </Note>
  </Tab>

  <Tab title="Technical Details">
    ### Analysis Pipeline

    The PL pipeline processes each uploaded file through three stages.

    #### Stage 1: File Parsing

    The CSV file is parsed into energy and intensity columns.

    #### Stage 2: Metadata Extraction

    The pipeline automatically parses the filename to extract sample identity, measurement location, laser power, exposure time, accumulation count, and energy range. Including these details in the filename enables automatic intensity normalization.

    #### Stage 3: Intensity Normalization

    When power, exposure, and accumulation are all present in the extracted metadata, intensity is normalized by dividing by the product of these acquisition parameters. Unit conversions (e.g., uW to mW, ms to seconds) are applied automatically. If any parameter is missing, normalization is skipped and raw intensity is preserved.
  </Tab>
</Tabs>