> ## 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.

# Get Ellipsometry Timeseries

> Retrieve ellipsometry measurement timeseries data

Returns processed ellipsometry timeseries data. Data is organized by property name (for example, film thickness or refractive index), where each property has its own arrays of timestamps and values sharing a common time axis.

<ParamField path="data_id" type="string" required>
  The data entry UUID for the ellipsometry measurement
</ParamField>

<ParamField query="return_null_if_missing" type="boolean" default="false">
  If `true`, returns `null` instead of an error when no timeseries data exists for this entry
</ParamField>

<ParamField query="last_n" type="integer">
  Return only the last N samples per property (useful for incremental fetching during live monitoring)
</ParamField>

<ParamField query="elapsed_seconds" type="number">
  Only return data points after this elapsed time (seconds). Useful for incremental fetching during live monitoring.
</ParamField>

<ParamField query="property_names" type="array">
  If set, only these property columns are returned. Omit to return all properties.
</ParamField>

<ParamField query="available_properties" type="boolean" default="false">
  If `true`, skip the data and return a metadata-only response listing the available properties
</ParamField>

## Response

<ResponseField name="properties" type="object">
  Mapping of property names to their timeseries data. Each key is a property name (e.g., `thickness`, `refractive_index`).

  <Expandable title="properties">
    <ResponseField name="relative_time_seconds" type="array">
      Array of time values relative to the start of the measurement (seconds)
    </ResponseField>

    <ResponseField name="unix_timestamp_ms" type="array">
      Array of Unix timestamps in milliseconds
    </ResponseField>

    <ResponseField name="values" type="array">
      Array of measurement values
    </ResponseField>

    <ResponseField name="units" type="string">
      Measurement unit for the values (e.g., `nm`)
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="property_units" type="object">
  Convenience mapping of property name to its unit
</ResponseField>

<ResponseField name="available_property_names" type="array">
  All property names recorded for this data entry, regardless of any `property_names` filter applied to the response
</ResponseField>

<ResponseField name="series_max_time" type="number">
  Maximum `relative_time_seconds` value across all properties
</ResponseField>

<RequestExample>
  ```python SDK theme={null}
  from atomscale import Client

  client = Client(api_key="YOUR_API_KEY")
  results = client.get(data_ids="d290f1ee-6c54-4b01-90e6-d701748f0851")
  ellipsometry = results[0]  # EllipsometryResult
  print(ellipsometry.timeseries_data)
  ```

  ```python Python theme={null}
  import requests

  response = requests.get(
      "https://api.atomscale.ai/ellipsometry/d290f1ee-6c54-4b01-90e6-d701748f0851/timeseries/",
      headers={"X-API-KEY": "YOUR_API_KEY"}
  )
  ellipsometry_data = response.json()
  ```

  ```bash cURL theme={null}
  curl "https://api.atomscale.ai/ellipsometry/d290f1ee-6c54-4b01-90e6-d701748f0851/timeseries/" \
    -H "X-API-KEY: YOUR_API_KEY"
  ```
</RequestExample>

<ResponseExample>
  ```json 200 theme={null}
  {
    "properties": {
      "thickness": {
        "relative_time_seconds": [0, 10, 20, 30, 40],
        "unix_timestamp_ms": [1705312200000, 1705312210000, 1705312220000, 1705312230000, 1705312240000],
        "values": [0, 4.9, 10.2, 15.0, 20.1],
        "units": "nm"
      },
      "refractive_index": {
        "relative_time_seconds": [0, 10, 20, 30, 40],
        "unix_timestamp_ms": [1705312200000, 1705312210000, 1705312220000, 1705312230000, 1705312240000],
        "values": [2.01, 2.02, 2.02, 2.03, 2.02],
        "units": null
      }
    },
    "property_units": {
      "thickness": "nm",
      "refractive_index": null
    },
    "available_property_names": ["thickness", "refractive_index"],
    "series_max_time": 40.0
  }
  ```
</ResponseExample>