Add output port to detector node.

Update documentation.

src/nodes/detector.rs

@@ -4,6 +4,7 @@ use crate::{
     optic_node::{Dottable, LightResult, Optical},
     optic_ports::OpticPorts,
 };
+use std::collections::HashMap;
 use std::fmt::Debug;
 
 type Result<T> = std::result::Result<T, OpossumError>;
@@ -17,17 +18,21 @@ type Result<T> = std::result::Result<T, OpossumError>;
 ///   - Inputs
 ///     - `in1`
 ///   - Outputs
-///     - none
+///     - `out1`
+/// 
+/// During analysis, the output port contains a replica of the input port similar to a [`Dummy`](crate::nodes::Dummy) node. This way, 
+/// different dectector nodes can be "stacked" or used somewhere in between arbitrary optic nodes.
 pub struct Detector {
     light_data: Option<LightData>,
 }
 impl Optical for Detector {
     fn node_type(&self) -> &str {
-        "light sink: detector"
+        "detector"
     }
     fn ports(&self) -> OpticPorts {
         let mut ports = OpticPorts::new();
         ports.add_input("in1").unwrap();
+        ports.add_output("out1").unwrap();
         ports
     }
     fn analyze(
@@ -35,14 +40,12 @@ impl Optical for Detector {
         incoming_data: LightResult,
         _analyzer_type: &crate::analyzer::AnalyzerType,
     ) -> Result<LightResult> {
-        let data = incoming_data
-            .into_iter()
-            .filter(|data| data.0 == "in1")
-            .last();
-        if let Some(data) = data {
-            self.light_data = data.1;
+        if let Some(data) = incoming_data.get("in1") {
+            self.light_data = data.clone();
+            Ok(HashMap::from([("out1".into(), data.clone())]))
+        } else {
+            Ok(HashMap::from([("out2".into(), None)]))
         }
-        Ok(LightResult::default())
     }
     fn export_data(&self, file_name: &str) {
         if let Some(data) = &self.light_data {