diff --git a/src/scgenerator/data/README.md b/src/scgenerator/data/README.md
index 0e2630e..5993dc4 100644
--- a/src/scgenerator/data/README.md
+++ b/src/scgenerator/data/README.md
@@ -6,5 +6,5 @@ Van der Waals constants : https://en.wikipedia.org/wiki/Van_der_Waals_constants_
 Chi3 : Wahlstrand 2012
 
 # `raman_response.csv`
-Raman impulse response recovered from measured gain spectrum. This is used then `raman_type` is set to `"measured"`.
+Raman impulse response recovered from measured gain spectrum. This is used then `raman_type` is set to `"measured"` (Stolen1989).
 
diff --git a/src/scgenerator/plotting.py b/src/scgenerator/plotting.py
index 0207c49..6f13b7b 100644
--- a/src/scgenerator/plotting.py
+++ b/src/scgenerator/plotting.py
@@ -230,7 +230,7 @@ def create_zoom_axis(
     return inset
 
 
-def corner_annotation(text, ax, position="tl", pts_x=8, pts_y=8, **text_kwargs):
+def corner_annotation(text, ax, position="tl", pts_x=4, pts_y=4, **text_kwargs):
     """puts an annotatin in a corner of an ax
     Parameters
     ----------
diff --git a/src/scgenerator/spectra.py b/src/scgenerator/spectra.py
index faefc12..85c56f5 100644
--- a/src/scgenerator/spectra.py
+++ b/src/scgenerator/spectra.py
@@ -202,12 +202,23 @@ class Spectrum(np.ndarray):
     def energy(self) -> np.ndarray:
         return np.trapz(self.time_int, x=self.t, axis=-1)
 
-    def mask_wl(self, pos: float, width: float) -> Spectrum:
+    def mask_wl(self, pos: float, width: float, preserve_sn: bool = False) -> Spectrum:
         """
         Filters the spectrum with a bandpass centered at `pos` of FWHM `width`.
         The FWHM is taken on the intensity profile, not on the complex amplitude
         """
-        return self * np.exp(-(((self.l - pos) / (pulse.fwhm_to_T0_fac["gaussian"] * width)) ** 2))
+        band = np.exp(-(((self.l - pos) / (pulse.fwhm_to_T0_fac["gaussian"] * width)) ** 2))
+        if preserve_sn:
+            dt = self.t[1] - self.t[0]
+            sn = np.fft.fft(
+                np.reshape(
+                    [pulse.shot_noise(self.w, dt) for _ in range(np.prod(self.shape[:-1]))],
+                    self.shape,
+                )
+            )
+            return self * band + np.sqrt(1 - band**2) * sn
+        else:
+            return self * band
 
     def measure(self) -> tuple[float, float, float]:
         """returns fwhm, peak power and energy"""