Laser wavelength calculation

#Grating equation:
#   d sin(θₘ) = m λ

#See also:
#   http://academia.hixie.ch/bath/laser/home.html
#   https://laserpointerforums.com/f70/make-your-own-spectrometer-under-1-a-98640.html

#Map of laser ID onto measurement tuples of form:
#   ( grating spacing (m / cycle),
#     distance to wall (m),
#     distance from mode 0 to mode 1 (m)[,
#     distance from mode 0 to mode 2 (m)[,
#     ...]] )
data = {
    "405nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 0.703),
    ],
    "445nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 0.796),
    ],
    "515nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 0.9585),
    ],
    "532nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 0.998),
    ],
    "638nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 1.3165),
    ],
    "650nm laser (test)" : [
        (1.0e-3/1000.0, 1.5885, 1.389),
    ],
}

for laser in sorted(data.keys()):
    l_ests = [] #in nm
    measurements = data[laser]
    for measurement in measurements:
        mode = 1
        for dist_mode in measurement[2:]:
            sin_theta = dist_mode * (measurement[1]*measurement[1]+dist_mode*dist_mode)**-0.5 #sin(arctan(dist_mode/measurement[1]))
            l_est = sin_theta * measurement[0] / mode
            l_ests.append(l_est * 1.0e+9)
            mode += 1
    print(laser + ": " + str(l_ests) + " nm")