Clock atom interferometry is an emerging technique in precision measurement, well suited for sensitivity enhancement through large momentum transfer (LMT). Although next-generation sensors aim for LMT factors beyond
104, their feasibility has been questioned due to potential impacts of laser frequency noise. We address this concern by analyzing the cumulative fidelity of sequential state inversions, showing that population error scales linearly with pulse number, not quadratically. Parasitic interferometer paths from imperfect pulses contribute negligibly, confirming that laser frequency noise is not a practical limitation.
Atom interferometry on optical clock transitions is being pursued for numerous long-baseline experiments both terrestrially and for future space missions. Crucial to meeting these experiments' required sensitivities is the implementation of large momentum transfer ($>
10^3\hbar k$). Here we show that to sequentially apply such a large momentum via
π pulses places stringent requirements on the frequency noise of the interferometry laser, finding that the linewidth is required to be considerably lower than has previously been suggested. This is due to imperfect pulse fidelity in the presence of noise and is apparent even for an atom at rest interacting with resonant light, making this a fundamental constraint on operational fidelity for a given laser and pulse sequence. Within this framework, we further present and analyse two high-power, frequency-stabilised laser sources designed to perform interferometry on the
1S
0 -
3P
0 clock transitions of cadmium and strontium, respectively operating at 332 nm and 698 nm.