added chirp to Gaussian pulses

tests/test_pulse.py

@@ -9,3 +9,26 @@ def test_pulse_envelope():
 
     assert np.trapz(sc.pulse.pulse_envelope(t, 10, energy=3) ** 2, x=t) == pytest.approx(3)
     assert (sc.pulse.pulse_envelope(t, 10, peak_power=3) ** 2).max() == pytest.approx(3)
+
+
+def test_chirp():
+    t = np.linspace(-10, 10, 1024)
+    f = sc.pulse.gaussian_pulse(t, 1, 1, chirp=1.0)
+    c = np.unwrap(np.angle(f))
+    c -= c.min()
+    assert pytest.approx(c, rel=1e-2, abs=1e-4) == t**2
+
+    params = sc.Parameters(
+        time_window=20,
+        t_num=1024,
+        peak_power=1,
+        wavelength=800e-9,
+        shape="gaussian",
+        chirp=1,
+        t0=1,
+        quantum_noise=False,
+    )
+    t2, f2 = params.compute("t", "field_0")
+    c2 = np.unwrap(np.angle(f2))
+    c2 -= c2.min()
+    assert pytest.approx(c2, rel=1e-2, abs=1e-4) == t2**2