diff --git a/src/scgenerator/evaluator.py b/src/scgenerator/evaluator.py
index 6568064..52985de 100644
--- a/src/scgenerator/evaluator.py
+++ b/src/scgenerator/evaluator.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 import itertools
 import traceback
 from collections import ChainMap, defaultdict
-from typing import Any, Callable, MutableMapping, NamedTuple, Optional, Type, Union
+from typing import Any, Callable, MutableMapping, NamedTuple, Optional, Union
 
 import numpy as np
 
diff --git a/src/scgenerator/parameter.py b/src/scgenerator/parameter.py
index 5ec8b6c..9a9bf5f 100644
--- a/src/scgenerator/parameter.py
+++ b/src/scgenerator/parameter.py
@@ -369,6 +369,7 @@ class Parameters:
     noise_correlation: float = Parameter(in_range_incl(-10, 10), default=0)
     width: float = Parameter(in_range_excl(0, 1e-9), display_info=(1e15, "fs"))
     t0: float = Parameter(in_range_excl(0, 1e-9), display_info=(1e15, "fs"))
+    delay: float = Parameter(type_checker(float, int), display_info=(1e15, "fs"))
 
     # Behaviors to include
     quantum_noise: bool = Parameter(boolean, default=False)
diff --git a/src/scgenerator/physics/pulse.py b/src/scgenerator/physics/pulse.py
index 9356a33..2e94b93 100644
--- a/src/scgenerator/physics/pulse.py
+++ b/src/scgenerator/physics/pulse.py
@@ -107,6 +107,7 @@ def initial_full_field(
     peak_power: float,
     w0: float,
     n0: float,
+    delay: float | None = None,
 ) -> np.ndarray:
     """
     initial field in full field simulations
@@ -125,6 +126,9 @@ def initial_full_field(
         center frequency
     n0 : float
         refractive index at center frequency
+    delay : float | None, optional,
+        if given, delays the pulse by that amount. This means that in the time domain, the pulse
+        won't be in the center of the window anymore.
 
     Returns
     -------
@@ -132,13 +136,15 @@ def initial_full_field(
         initial field
     """
     return (
-        initial_field_envelope(t, shape, t0, peak_power)
+        initial_field_envelope(t, shape, t0, peak_power, delay)
         * np.cos(w0 * t)
         * units.W_to_Vm(n0, effective_area)
     )
 
 
-def initial_field_envelope(t: np.ndarray, shape: str, t0: float, peak_power: float) -> np.ndarray:
+def initial_field_envelope(
+    t: np.ndarray, shape: str, t0: float, peak_power: float, delay: float | None = None
+) -> np.ndarray:
     """
     returns the initial field
 
@@ -153,6 +159,9 @@ def initial_field_envelope(t: np.ndarray, shape: str, t0: float, peak_power: flo
         `scgenerator.physics.pulse.fwhm_to_T0_fac[shape]`
     peak_power : float
         peak power
+    delay : float | None, optional,
+        if given, delays the pulse by that amount. This means that in the time domain, the pulse
+        won't be in the center of the window anymore.
 
     Returns
     -------
@@ -164,6 +173,9 @@ def initial_field_envelope(t: np.ndarray, shape: str, t0: float, peak_power: flo
     ValueError
         raised when shape is not recognized
     """
+    if delay is not None:
+        t = t + delay
+
     if shape == "gaussian":
         return gaussian_pulse(t, t0, peak_power)
     elif shape == "sech":
@@ -382,11 +394,41 @@ def adjust_custom_field(
     input_time: np.ndarray,
     input_field: np.ndarray,
     t: np.ndarray,
-    intensity_noise: float,
-    noise_correlation: float,
-    energy: float = None,
+    delay: float | None = None,
+    intensity_noise: float | None = None,
+    noise_correlation: float | None = None,
+    energy: float | None = None,
     peak_power: float = None,
 ) -> np.ndarray:
+    """
+    When loading a custom input field, use this function to conform the custom data to the simulation
+    parameters.
+
+    Parameters
+    ----------
+    input_time : np.ndarray, shape (m,)
+        time axis of the custom data
+    input_field : np.ndarray, shape (m,)
+        complex field values
+    t : np.ndarray, shape (nt,)
+        time axis of the simulation
+    delay : float | None, optional
+        if given, delays the pulse by that amount. This means that in the time domain, the pulse
+        won't be in the center of the window anymore.
+    intensity_noise : float | None, optional
+        if given, pick a value `delta` on a normal distribution such that, when considering an
+        ensemble of similar input fields, the relative `intensity_noise` is the specified amount.
+        by default None
+    noise_correlation : float | None, optional
+        if given, correlation factor between intensity noise and pulse width variations
+        by default None
+    energy : float | None, optional
+        if given, readjusts the amplitude of the field such that the total energy is the specified
+        value. Takes precedence over peak_power, by default None
+    peak_power : float | None, optional
+        if given, readjusts the amplitude of the field such that the peak power is the specified
+        value, by default None
+    """
     field_0 = interp_custom_field(input_time, input_field, t)
     if energy is not None:
         curr_energy = np.trapz(math.abs2(field_0), t)
@@ -405,8 +447,11 @@ def adjust_custom_field(
 
 
 def interp_custom_field(
-    input_time: np.ndarray, input_field: np.ndarray, t: np.ndarray
+    input_time: np.ndarray, input_field: np.ndarray, t: np.ndarray, delay: float | None = None
 ) -> np.ndarray:
+    if delay is not None:
+        t = t + delay
+
     field_interp = interp1d(input_time, input_field, bounds_error=False, fill_value=(0, 0))
     field_0 = field_interp(t)
     return field_0