1：Experimental Design and Method Selection:

The study utilized aligned single-wall carbon nanotubes (SWCNTs) films prepared from high-quality SWCNTs with an average diameter of 1.5 nm and average length of 6 μm using a slide-coating technique. The photoelectron emission was studied as a function of laser power, photon energy, polarization, and bias voltage.

2：5 nm and average length of 6 μm using a slide-coating technique. The photoelectron emission was studied as a function of laser power, photon energy, polarization, and bias voltage. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: A film of aligned SWCNTs with a thickness of 1.67 μm and a 2D nematic order parameter of 0.7 was used. The work function was determined to be 5.17 eV using ultraviolet photoelectron spectroscopy.

3：67 μm and a 2D nematic order parameter of 7 was used. The work function was determined to be 17 eV using ultraviolet photoelectron spectroscopy. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: The photoemission was conducted in a vacuum chamber with a base pressure of ~ 10-7 torr. The light source was a Coherent Libra, delivering a train of 116-fs-long pulses centered at 800 nm at 1 kHz, which was frequency doubled to generate 138-fs-long pulses of radiation centered at 400 nm.

4：Experimental Procedures and Operational Workflow:

The beams were collimated with 1/e2 diameters of 3 mm and 2 mm, respectively. The power and polarization of each beam as well as the delay between the two were controlled in a bichromatic Michelson interferometer. The two beams were collinear and directed onto the sample at a 30° incidence angle.

5：Data Analysis Methods:

The photocurrent was measured as a function of bias voltage and laser power, and the data was analyzed to determine the order of the multiphoton process and the response time of the photoelectron emission.